Q. I have three acrylic-on-canvas paintings that hung in a restaurant for more than 20 years, and they’re dirty from cigarette smoke. Can they be fully restored, and will it require hiring an art restoration company?
A. Most smoke-damaged paintings can be restored to their original beauty, and the removal of smoke and other surface grime is a common procedure for all kinds of paintings. Typically this is done by a professional, and that would probably be the safest course of action for you, but you can also try the following procedure.
Working on a small area of the painting at a time, under magnification, conservators often remove this type of buildup with nothing more than a small cotton swab slightly dampened with water. But this must be done with caution because any cracks in the paint and the ground layers may allow moisture from the swab to reach the canvas. Most linen and cotton canvas supports aren’t treated to prevent shrinkage, as clothing fabrics are, so the application of moisture poses a significant risk of shrinking your canvas. If this happens the paint may begin to flake off, and a minor cleaning problem could quickly grow into a major conservation issue.
If you find the buildup particularly hard to remove, a very small amount of detergent may be added to the water, or the dampened swab may be rolled across a bar of Ivory soap and then rolled across the painting. Either of these procedures should be followed by using a couple of swabs dampened with clear water to remove the soap residue. Like all conservation procedures, this process should first be tested in a small area of the painting and immediately terminated if you find color being removed.
Acrylic paintings usually have far fewer cracks than oil paintings of the same age, so cleaning your paintings will be less risky than cleaning an oil painting would be. If they’ve been varnished, however, watch out for blanching, which is the cloudy white appearance of a varnish that has been in contact with moisture (you’ve probably seen the white rings left on furniture from a wet glass). Blanching can be a particular problem if your painting is varnished with a natural resin such as damar or mastic varnish, but these are rare cases because most acrylic paintings have a synthetic resin varnish. Again, it’s important to test first before going too far.
If you have any reservations about this process, call your local museum and ask them to recommend a professional conservator, or try telephoning the American Institute for Conservation of Historic and Artistic Works at 202/452-9545 for a recommendation.