At your disposal: oils and solvents

Q. Our painting studio, where we teach oil painting, needs some sort of system to catch brush-cleaning waste. We receive federal grants and need to be in compliance with federal and state environmental regulations. Can you provide information on which disposal system we need and where it can be purchased?

A. This is an excellent question. Golden Artist Colors’ has a Web page ( that offers good information about hazardous waste disposal. The Web site’s advice applies to all sorts of paints.

As a member of the University of North Carolina-Greensboro Department of Art, I helped develop some standard brush-cleaning methods. There’s actually no need to buy a complete “system” for disposal, but you’ll need some basic equipment.

First, you’ll need three 5-gallon plastic buckets for each painting studio. We call these Tub A, Tub B and Tub C. You’ll fill each bucket about one-third of the way with water, and put a cup of ordinary detergent in Tub A. All Tubs are recharged with water, and soap is added to Tub A every day.

Next, you’ll need 30-gallon drums, which we call “white drums.” We use these drums to collect all waste-water and then hire a licensed disposal service to pick them up. Find one of these services by looking in the Yellow Pages under “Hazardous Waste Removal” or “Rubbish and Garbage Removal.” We generally store one drum near the sink. Additionally, you should have rags or paper towels handy before you start cleaning your brushes.

Steps for brush-cleaning
The basic process for cleaning brushes is the same no matter what paint you use. Follow these guidelines:
1. Rinse brushes in a small, resealable container of the appropriate solvent—odorless mineral spirits for oil, alkyd, resin-oil, enamel, encaustic and other solvent-thinned paints; soap and water for acrylics, poster paints or temperas, transparent and opaque watercolors, and other water-thinned paints.
2. Wipe brushes clean of paint and solvent residue on a rag or paper towel.
3. Rinse brushes of remaining paint and solvent residue in inexpensive, ordinary vegetable oil; use water instead of vegetable oil to rinse acrylics, poster paints, watercolors and other water-thinned paints. Then wipe brushes on a rag or paper towel.
4. Wash the paintbrushes with the soapy water in Tub A, then rinse well in clean water in Tub B. Finally, rinse the brushes in the clean water of Tub C.
5. Shape the brush heads and allow them to air-dry. Store dry brushes in a closed container to prevent the accumulation of dust. After several washes, the water in Tub A will become too dirty. When this occurs, you should put the water in the white drum next to the sink. You then can put the water from Tub B into Tub A, but add some more detergent to Tub A. Next, put the water from Tub C into Tub B and fill Tub C with fresh tap water. Remember: Never pour the dirty water down a sink. Use the sinks only to wash your hands.

Disposing liquid solvents
Unwanted or waste solvents (except water), oils (including vegetable oils), and mediums should be put into a cylindrical, red, fire-safe liquid waste can located next to the sink. You can get these trash cans at Lab Safety Supply (800/356-0783; You should put wastewater used for thinning or rinsing in the white drums as described earlier. Make sure to keep the lids to all these containers closed, except when waste is being added, and always clean up any spills immediately. Never use sinks or toilets for disposing solvents, as it’s illegal and harmful to the environment.

To get rid of any unwanted paint, including palette scrapings, collect them on a paper towel or rag. Then dispose of rags and paper towels contaminated with paint and solvents, or which have been used to clean brushes and palettes, in fire-safe trash containers. As always, remember to keep the lids to these containers closed. These materials may not be disposed of in ordinary trash cans because they pose a fire hazard. It’s illegal to dump them with ordinary trash as they may harm the environment.

Unwanted or failed art projects contain environmentally harmful ingredients, too, and shouldn’t be disposed of in ordinary trash. Break these objects into small pieces and put them in the fire-safe trash containers.

And remember: You’re responsible for removing unwanted furniture or trash from your studio and putting it in the nearest dumpster. Don’t leave these objects in a hallway because objects in a hallway violate insurance regulations and can block an emergency exit from the building.

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