Safe Solvents

S a f e r Solvents and Solutions

Water as a Solvent

Water is sometimes referred to as the universal solvent. It possibly is also the only truly ‘safe’ solvent. Its capability to thin or dissolve other substances is the basis of many biological processes and is essential for the functioning of our bodies. Our system is intricately adapted to its essential presence, so water is more than just being nontoxic: it is linked to our very force of life.

When an ionic or polar compound enters water, it is surrounded by water molecules. The small size of water molecules typically allows many water molecules to surround one molecule of solute. The partially negative dipoles of the water are attracted to positively charged components of the dissolved substance, and vice versa for the positive dipoles. Liquid water has a partially ordered structure in which hydrogen bonds are constantly being formed and breaking up – it is in a constant state of dynamic movement and flux. These strong bonds explain why droplets of water can stay linked as a unit on a hard surface.

Liquid water (H2O) has a partially ordered structure in which hydrogen bonds are constantly being formed and breaking up. This is a unique chemical bond that is never permanent, but in a constant state of change.

The powerful dissolving properties of water have long been exploited in all kinds of water soluble paints and inks (such as water color, gouache, or block printing ink), but for centuries the stereotypical notion of oil and water dont mix prevented further development. Due to this notion, whenever oils needed dissolving hydrocarbon agents such as turpentine or mineral spirits were employed, not water.

Over the past three decades a quiet revolution has taken place which puts water back in its place as the superior solvent. New knowledge makes water equally suitable as a safer solvent for oil based paints and inks. The revolution started when acrylic polymers became entirely water soluble in the early seventies, and it now carries on with the widespread introduction of water miscible oil paints and printing inks.

Dish Soap, Detergents, and General Purpose Cleaners

images shown for reference only

Many print studios and artists use a mixture of domestic dish soap (washing up liquid) and water mixed in a spray mister as a universal cleaning and de-greasing agent. The current crop of many of these products is so concentrated that usually a 5% – 10% solution suffices to make a strong cleaning agent.

Some cheaper brands of dish soap should be avoided as they are not strong enough to lift greasy ink or paint deposits. Or, use one of the many green products now available.

Avoid inhaling spray mist and wear gloves during use. When cleaning oil-based inks vegetable oil is used in the first instance to lift the bulk of the ink residues (see below).

Vegetable Oil for Ink Clean-Up

nontoxic cleanup of oil based ink: use a spatula or plastic kitchen scourers to work the cleaning oil into the ink. The action is not instant (as with mineral spirits); it takes a minute or two for the vegetable oil to effectively absorb the printing ink.

Vegetable oil, (canola or rapeseed oil, sunflower oil) has become on of the most commonly used cleaning agents in the print studio. Using a soaking approach (see picture) vegetable oil is very effective at dissolving the bulk of oil based printing inks from inking slabs and plates. Usually surfaces are then cleaned with a strong dish soap solution or a commercial degreasing agent such as Green Works general purpose cleaner.

If any inky residues remain use a small amount of baby oil to lift these from plate surfaces – baby oil is a lighter grade of oil than vegetable oil and the two can successfully be used in succession.

Alternatively, use SoySolv II to completely clean plates from ink residues (see below). After lifting the bulk of the ink residues from plates and ink slabs with cleaning oil surfaces are usually de-greased and fully cleaned with a dish soap solution or general purpose cleaners and plenty of water as described above. Metal etching plates are often left with a slight greasy deposit for storage, as this may prevent oxidization.

Olive oil has a variety of uses in art making. The Romans used it as a binder for making oil paints, as a hand cleaner, and as body lotion. One of the mildest paint strippers – Marseilles Soap – is also made from olive oil. It is a nontoxic alternative to baby oil made from crude oil (this is thought to create conditions for asthma in babies).

Today, olive oil makes an ideal hand cleaner and brush cleaner after a session of using oil paints. The use of olive oil prolongs the life of your brushes. For general cleaning use the cheaper vegetable oils.

Baby Oil (Mineral Oil)

Baby oil (mineral oil) is a popular cleaning solvent used by printmakers and painters. Baby oil is made from refined mineral oil as a byproduct of the oil refinery process. Although it can generally be recommended as a safer alternative to volatile solvents in the print studio some caution is needed as there are some concerns over the health effect on the kidneys, (and it is thought that used on babies it may cause asthma). Wear gloves and dispose of residues in fireproof safety containers. Different grades of mineral oil have long been used as the main ingredient of industrial printing inks, but due to health concerns many in the industry are now switching over to soy and vegetable oils as the base for printing inks. Especially the lower grades of mineral oil are known to be neurotoxic as they contain trace amounts of hydrocarbon solvents.

Washing Soda (Sodium Carbonate) Solution

Washing Soda, sodium carbonate, or soda ash, is a safe yet powerful alkaline that can break down many kinds of ink, paint, and acrylic in a strong solution with water. Typically this kind of dissolving process takes place through immersion in a concentrated sodium carbonate bath (say 1part washing soda in 3 parts water).

Chemists refer to this as saponification: long paint or polymer molecules (or long oily molecules) are broken down into short chains of esthers…ink and plastic can turn into soap.

Sodium carbonate is also found in laundry detergent. Washing Soda is a staple ingredient of acrylic resist etching, and most photopolymer films such as ImagOn are developed in a mild solution of it. Use warm water to dissolve the crystals and make sure you wear a dust mask when handling the soda ash powder – it is corrosive and it may irritate the mucous membranes. Also avoid direct skin contact.

In general, this widely available and inexpensive chemical is a much safer yet very effective alkaline stripping agent than the more hazardous alkalis such as sodium hydroxide and potassium hydroxide with their volatile reactivity. Print studios usually purchase sodium carbonate in bulk from chemical wholesale.

Uses range from making up individual stripping baths for single use to entire stripping tanks that can last for weeks or months. Once a sodium carbonate solution weakens it turns thick and viscous and it should be replaced, neutralized with some vinegar or citric acid, and discarded.

Baking Soda

or sodium bicarbonate, is a popular nontoxic cleaning product, now used in many eco-aware households. Baking Soda is mildly alkaline, and mixed to a paste with water it is a great de-greasing agent. It can remove thin paint and ink deposits, especially through soaking. The fine powder also makes a good base for metal polish (mix with white vinegar). Not to be confused with washing soda (see above).

Ethyl Alcohol

Ethyl Alcohol, or ethanol alcohol is the safest kind of alcohol available. It has better health and safety characteristics than isopropanol (rubbing alcohol), which still is the most commonly used de-greasing agent in most print studios. Isopropanol (isopropyl alcohol) shares many of the neurotoxic hazards as other solvents such as white spirit.

If you need to use alcohol for de-greasing or cleaning use ethyl alcohol – our bodies are much better adapted to its assimilation, this is why it is drinkable in alcoholic beverages. Beware of the fire hazard, wear gloves during use, and dispose of any residues in safety containers. Available from pharmacies, drug stores, and chemical wholesale.

IMPORTANT: ALL LIQUID, VOLATILE, HYDROCARBON-BASED
SOLVENTS REQUIRE SOME FORM OF RESPIRATORY PROTECTION
(this includes both petroleum products, but also bio-based solvents,
such as ethyl alcolhol, soy/ethyl lactate, orange oil,
and many others).

Is Alcohol bad for you?

spirits (Wikipedia)

However, very compelling studies from November 2022 revealed shocking new evidence that the widely held view of health benefits of moderate alcohol exposure / or consumption is simply false, and needs to be revised. That small tipple, or the occasional glass of wine, scientifically speaking, is not good for your health after all. The evidence shows that significant DNA damage occurs in the body every time alcohol is consumed, and the alcohol itself also acts as an agent that blocks cell and DNA repair. For the first time, and based on clinical evidence, alcohol is now also regarded as a known carginogen. (source: New York Times, 2023)

Further Reading: ‘Even a Little Alcohol Can Harm Your Health, Dana G. Smith, NYT, Jan 13, 2023

Vinegar

White Vinegar (a natural 5% solution of acetic acid) is a cheap, popular and powerful de-greasing agent. In a 50/50 mix with water it can be used as a substitute for the chemical window cleaners that invariably contain glycol ether (a neurotoxin). In print studios it can be used for cleaning glass surfaces, and mixed with baking soda for general cleaning. The acidy smell quickly evaporates, but is not to everybody’s liking. Make sure you purchase sugar free vinegar. More info on its many uses can be found on: http://www.vinegarworkswonders.com. The 50/50 mixture is also used to stabilize photo-polymer plates after development. A vinegar / water / salt mix can be employed as an effective metal de-oxidizer for copper and brass in acrylic resist etching.

Orange Oil Cleaners & D Limonene

Safer Stripping and Cleaning
with Orange Zest Solvents

There is a growing number of citrus-based solvents on the market. The key ingredient, D-Limonene, also known as orange oil, the possibly safer and innovative solvent extracted from orange peel, can be purchased directly from the citrus industry. For example, see http://www.citrusdepot.net. This solvent is more powerful than mineral spirits, strong enough to dissolve hardened acrylics, oil paint, printing ink, (and even some plastics) , yet medical studies have found less carcinogenic or neurotoxin hazards to humans comparable to the petrochemical solvents.

Users should, nevertheless, handle the solvent with care: ensure good ventilation and take fire precautions when using the new orange oil solvents. Unlike oil-based products, orange oil is considered biodegradable. Concentrated orange oil is a very powerful – not a benign – chemical that dissolves plastic and fats, hence should be treated with respect, as misuse of the concentrated oil can cause harm to the body. Extreme exposures are known to have caused lung damage in users.

A variety of citrus-based safe solvents are on the market (such as ‘D*Solve’, ‘CitraSolv’, or ‘De-Solv-it’). These remove acrylics, etching grounds and hardened ink and paint. ‘CitraSolv’, or ‘De-Solv-it’ are made for the DIY mass market and can be purchased in hardware and DIY super stores.

Mark Zaffron’s – ZAcryl ‘DSolve’ – was sold trough printmaking and art materials suppliers. Products such as ‘DSolve’ utilized D-Limonene sparingly and mixed with milder ingredients to avoid hazardous solvent concentrations, and to reduce any fire hazard. The product is no longer available, but other companies make similar products (see below). Make sure you read ‘msds’ safety information. Also something to watch out for: some of the bigger brands of ‘citrus’ solvent mix their plant derived solutions with conventional petroleum derived materials to cut cost (neurotoxins).

“This truly revolutionary solvent was formulated as an alternative to petroleum-based turpentines and thinners. It is made from 100% renewable agricultural resources of soy, corn, and citrus, and is non-polluting, non-carcinogenic, and bio-degradable. Less than a teaspoon will thoroughly clean a large plate. DSolve will even strip dried ink from etched lines.” Dick Blick  (company quote)

IMPORTANT: ALL LIQUID, VOLATILE, HYDROCARBON-BASED SOLVENTS REQUIRE SOME FORM OF RESPIRATORY PROTECTION

(this includes both petroleum products, but also bio-based solvents,such as ethyl alcolhol, soy/ethyl lactate, orange oil, and many others)

below, a similar product, made for artist use: ‘NaturalEarthPaint’ (https://www.naturalearthpaint.com).

https://naturalearthpaint.com/products/fine-art-supplies/

This website also contains a useful and informative ‘how-to’ page on making your own traditional painting mediums, using simple ingredients and recipes (Gouache, Egg Tempera, etc.)
Natural Paint Recipes
“Does not irritate the skin / Does not emit harmful vapors. / Soy-based” (company quote).

 SAFETY NOTE: NEVER INHALE CONCENTRATED VOC’s!  concentrated VOCs when inhaled (including plant-derived VOCs) may cause lung damage or even death by asphyxiation  D-Limonene Safety The active ingredient in orange oil, D-Limonene is a natural yet very powerful solvent. In concentrated form and vaporized it may present a significant inhalation hazard; also it is highly flammable. If using substantial amounts of pure orange oil and over prolonged periods, work in a well ventilated area, and ideally also use an organic vapor mask. Most citrus based solvents utilize the power of this natural paint thinner in aqueous solutions, and accompanied by other ingredients such as soy oil and corn oil and detergents.

Research into Bio Solvents

The now established bio solvent industry conducts some of the research into safer solvent, paint and ink alternatives
not all their solutions are as safe as claimed!

Two companies supplying ingredients for bio-solvents and volume supplies for industrial use (for instance in the printing industry) are Citrus Depot and Vertec Biosolvents. Both of these firms conduct leading research and development into nontoxic solvent technologies.
Vertec claim to be ‘the world’s most innovative supplier of sustainable biobased solvents derived from corn, soybeans, citrus fruits and other renewable feedstocks’, and the company also pursue a carbon-neutral policy. The company just announced a new product – its ‘DLR blend’, a cheaper and environmentally friendly alternative to d-limonene, which may have uses and applications in painting and printing. 
Citrus Depot http://www.citrusdepot.net/ 
Vertec BioSolvents http://www.vertecbiosolvents.com/

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‘turpenoid Natural’ is an extremely effective nontoxic brush cleaner and gentle brush conditioner which rinses out with plain water. Brushes are reconditioned when cleaned with Turpenoid Natural®. It is non-flammable, does not irritate skin or eyes and does not emit harmful vapors. It is an effective painting medium when used within recommended guidelines.

Use in paint mediums should not exceed 25% to ensure proper drying time. It designed for use in oil painting brush baths / is a highly effective brush cleaner and conditioner, even for brushes with dried oil, alkyd or acrylic paints / emits no harmful vapors / requires no special ventilation / conditions brushes as it cleans /rinses out with plain water / is nonflammable & noncombustible / will not deplete the ozone layer / Safe for the environment (Weber).

SoySolv II Environmentally Safe Industrial Cleaning Solvent Made from 100% soybean oil, SOYsolv® is tested and proven to be a safe, effective and powerful product for use in many applications. Nontoxic and Biodegradable. This product is used in various print studios in combination with vegetable oil as a final cleaner for inked plates. The product leaves a slightly greasy deposit; follow up with de-greasing. Not very suitable as a stripper for acrylics – use washing soda or a citrus based product instead (D-Solve).

Raw Linseed Oil is the main ingredient in many inks and in oil paint. A natural nontoxic oil made from flax seed that can be used for oil paint thinning, cleaning, and brush cleaning; it is relatively slow drying. The boiled variant of linseed oil is faster drying but typically contains solvents, hence the need for safety precautions for boiled linseed oil. The Greeks and Romans used other types of vegetable oil in their paint making – mainly olive oil – , but linseed oil became the paint making oil of choice in Europe in the Middle Ages. It’s main disadvantage lies in its tendency to crack when applied too thickly and with age. Although olive oil makes a great brush cleaner and conditioner (and should be used as ‘baby oil’ – on babies- instead of mineral oil), it is less suitable for paint making as it is too slow drying.

Marseilles Soap

is a brush cleaner that the old masters of the Renaissance are thought to have used. Make a strong solution of this soap in warm water (best produce small chippings with a cheese grater – these dissolve better); great for brush cleaning and conditioning and for cleaning hands after painting. Makes an effective and completely safe paint stripper by soaking implements for several hours or overnight; even works on hardened acrylics and oil paints.

Flocculation / Purification of waste acrylics

dealing with waste water and paint residues

images from left:
food-grade Alum | black acrylic paint removed from water |
matte medium removed from solution (right)

Clarifying agents are used to remove suspended solids from liquids by inducing flocculation (the solids begin to aggregate forming flakes, which either precipitate to the bottom or float to the surface of the liquid, and then they can be removed or collected) (Wikipedia).

The solid residues produced in this manner can be disposed of as dry waste.

One of the most commonly used ‘flocking’ agents in industry, and by paint manufacturers, is the ‘double salt’ ALUM, which to artists is available as a food additive and from drug stores.
The makers of acrylic paint sometimes use flocculation to manage waste water streams / purify waste water.

Using a concentrated alum solution in pure warm water, can be a very efective method for removing monomeric compounds from wash-out water in used or left over acrylic paints, latex, glues, or photo-polymer development solutions.

Flocculation Method:
dissolve Alum crystals in warm water
and allow to mix well, then mix this
with the acrylic waste solution,
while stirring.
Some acrylics solidify instantly,
while others may take a few
minutes to form solid particles.

You may also consider adding absorbent matter to the mixture, to remove any paint residues more fully. For example, adding some chalk, torn up waste paper or card, or woodchips will help with bulk removal of chemicals and coloring agents. In scientific tests also organic matter such as leaf mulch was used very successfully, as there are additional bacteria and enzymes that may aid the removal and breakdown of chemicals. In industrial settings and municipal waste water systems walnut shells (crushed) are the preferred medium for water purification in settling tanks. (walnut shells are easy to buy cheaply on Amazon, Etsy etc.).

additional research observation:

Alum was successfully used to fully separate out and solidify a variety of
dissolved acrylics and acrylic mediums from water.

An Alum solution also appears to have a ’separating’ effect on oils or grease dissolved in water.
Although no solids are formed as such, a water/oil mixture can be made to
separate much more strongly by introducing alum, possibly through
enhancing the reciprocal repulsion of grease and water, making it
much easy to remove the oil from water by straining it off.

It seems likely that the use of Alum solution might have potential
benefits and applications in the medium of
lithography –– which is all about maximising
the opposition of grease and water –– for instance as wetting agent
or an anti-scumming solution.

Safer Metal Polish

‘BlueMagic’ Metal Polish Cream polish works on all metal surfaces and is non-abrasive. Works great on chrome, aluminum, brass, copper, sterling silver, stainless steel or gold. Removes tarnish and oxidation, provides a lasting protective coating and can be used with buffers and polishers.
According to the manufacturer’s msds information the product can be regarded as safe, as it does not contain harmful solvents like similar products (‘Brasso’ etc.). Recently printmakers discovered its use as an etching ground ingredient (Van Oppen studio).

Geowash K ‘the ultimate VCA’

‘To our knowledge this is the most environmentally friendly (and active) solvent / detergent on the market (Polymetaal)’.
The detergent Geowash K is based on vegetable oils. This detergent is suitable for removing wax-based etching-grounds, litho crayon, litho-tusche, oil-based printing inks, oil paints and lacquers.
(V.C.A. = vegetable cleaning agent). The Original text on the label (designed for commercial printers) reads as follows:

Universal Cleaner for blanket and press rollers based on natural substances (> 95%).
Miscible with water, plate friendly, no smell, use it sparingly, high detergency. Generally, rinse with water. Free of aromatics. Flash point 145 ° C
Practical Usage Instructions by Ad Stijnman Polymetaal

D&S BioLaq

The new company D&S offer ‘nontoxic’ solvents and laquers for lithography etching
‘BioLaq: ‘Superior Replacement for Asphaltum and Plate Lacquers’.
Excellent hard ground for etching’ (‘no hazmat’: Graphic Chemical Co)

Safer Offset Chemistry: some examples

– ‘Böttcher 260’ Newspaper Roller and Blanket Wash Böttcher 260 wash is a very safe, low odor, non-hazardous wash formulated for the newspaper industry. It is very mild on the rollers and blankets and it offers a much lower safety and health risk than traditional washes on the market. It is a clear solvent with a pleasant odor. Flashpoint 203°F http://www.bottcher.com

– ‘Varn Safety UV Cleaner’ is one of the only effective cleaners for UV inks that does not rely upon harsh solvents.
Most UV washes contain large amounts of solvent EB. This is also known as 2-butoxyethanol or butyl cellosolve®. Varn Safety UV Cleaner does not contain solvent EB, which is a hazardous air pollutant under the Clean Air Act. Varn Safety UV Cleaner appeals to the UV ink and coating user who also requires a strong and safe cleaner.

– ‘Varn® VWM Wash’ is a water miscible, one step wash formulated to meet ecological requirements for safety in roller and blanket washes.

Essential Oils as binders and solvents

There is a new movement especially among oil painters towards essential oils derived from seeds, nuts, flowers and plants. It is clear many of these have been used historically as painting mediums, and there may be significant health-related advantages. Considering that some of these oils are also highly volatile, it can be expected that the use of some of these natural solvents in larger amounts may require some ventilation or respiratory protection for complete peace of mind.

Overall, mediums such as Spike Lavender oil appear to be a much safer alternative to turpentine or mineral spirits, but as is the case with most ‘natural turpenoids’, there is the possibility of adverse effects, as mentioned on Wikipedia: (Lavender Oil)
Adverse effects
Lavender oil appears to be an endocrine disruptor, exhibiting anti-androgenic activity in vitro.
Lavender oils in soaps, shampoos, and other skin applied medications may cause prepubertal gynecomastia, which is breast development in young boys.[12] This suggests that repeated exposure to lavender oil may promote adverse symptoms and effects. These oils can also result in skin irritation and other allergic reactions when in contact with skin, causing nausea, vomiting, dizziness, and overall bodily discomfort

One American Art Materials firm recently published an overview of Oil Painting Solvents and Essential Oils that also contains some detailed historical information: click here for the full text on their website https://www.jerrysartarama.com/images/PDFs/Artists-Guide-to-Oil-Painting-Solvents.pdf

an excerpt from the introduction section of this guide:

I. The most common solvents used today are Turpentine and Odorless Mineral Spirits
A. Turpentine: WHAT IS IT? 

Turpentine is made from tree sap that is secreted by conifer trees (like pine, cypress, fir, larch, fir), where the tree sap is distilled to separate the oil from the resin, creating the solvent known as Turpentine. The process to industrially distill the tree sap (and the wood that produces the sap) often uses naptha and chemicals to extract the most solvent possible. Tree sap is an oleo-resin that acts as the trees natural bug repellant, so it makes sense that the distilled solvent from it would be toxic to breathe. Because of headaches and health issues related to the use of Turpentine (primarily since the 1950s), the principal substitute has been Odorless Mineral Spirits. B. Odorless Mineral Spirits: WHAT IS IT?
1. Odorless Mineral Spirits is made from distilled petroleum, with chemicals added to the petroleum distillate to eliminate the strong odor. This addition does not remove the toxic fumes from the product; rather, it only makes them less detectable to the senses. It is advertised as less toxic than Turpentine because it evaporates more slowly than Turpentine, but essentially it is de- odorized distilled industrial gasoline that is toxic to breathe but has a low odor so people do not notice the toxic fumes.
  II. Essential Oils- HISTORICALLY DOCUMENTED PAINT THINNERS/SOLVENTS
Essential oils are one of three types of oils, all produced from organic material, which can be classified as: fixed non-drying oils, drying oils, and essential oils. They all mix readily together and thus are soluble in each other. For oil painting we are only concerned with the drying oils and essential oils
a. Fixed non-drying oils e.g. olive oil, vegetable oil:i. Produced by pressing fruit, vegetables or plants. ii. When these oils come into contact with oxygen, they do not dry into a solid or evaporate, they remain in their liquid state. b. Drying oils e.g. linseed (flaxseed), walnut: i. Drying oils are produced by pressing the seeds of fruits, plants. ii. When these oils come into contact with oxygen, they dry and become hard: they change from a liquid state to a solid state. They are used as the main vehicle mixed with pigment to make oil paints.
c. Essential oils e.g. Spike Oil, Rosemary Oil:i. Essential oils are produced from flowers and plants through a process of distillation, rather than pressing.

Some historic examples are Lavender Spike Oil, which is made from the spikes of a species of lavender flower, and rosemary oil.  ii. When essential oils come into contact with oxygen, they transform from a liquid state to a gaseous state; in other words, they evaporate like Turpentine and Mineral Spirits. iii. This evaporating property is one reason among others that essential oils are successful paint thinners and solvents since the Renaissance. (use the above link for the full text)

Goodbye to Turpentine | Safe Oil Painting

by Robert Maynard

Safer Paint Strippers

Exposure to some common paint stripping products
can be very hazardous, and even fatal.
OSHA lists several safer alternatives
on their pages.

Fatal Incident involving Paint Stripper | OSHA

in progress:
safer MEDIUMS and BINDERS
methyl cellulose
gum arabic
gouache / watercolor
glycerin
PVA
(archival)