Canvas is a durable cloth material that is usually stretched across and tacked to wooden frames. This frame is then prepared for painting. If you own an older canvas painting it may be covered in dust or spotted with fungus. Cleaning works on canvas is simple, but it requires a delicate touch and the correct supplies. Anything too abrasive may damage the paint or warp the canvas.
Lay the canvas on a firm, flat surface. Gently sweep the painted side of the canvas with a soft-bristled paintbrush to remove obvious surface dirt and dust. Repeat this process for the back of the canvas.
Put on latex gloves to protect the painting from skin oils. Prepare two cleaning swabs by placing one sterile cotton ball on the tip of each skewer stick.
Moisten one swab with emulsion cleaner and the other with varnish remover. Test which solution is a more effective cleaner by rolling each cotton ball onto a small area of the painting. The ball that picks up more dirt and yellowed varnish will be the best choice.
Apply neutralising solution to a third cleaning swab and roll it over the test area. This stops the cleaning action until you are ready to continue.
Moisten swab with your choice of either emulsion cleaner or varnish remover. Begin cleaning the painting, using a gentle rolling motion to apply. Work slowly and only cover a small square area at a time. Apply neutraliser to each area after it has been cleaned. Use fresh cleaning swabs as needed. Check each used swab to ensure that it is not removing any pigment from the painting.
Dampen a swab with a light varnish. Apply gently to the surface of the painting after you have completed cleaning. Use the same gentle rolling motion you used for cleaning.
Allow the canvas to set undisturbed overnight.
Materials required can be found at your local fine arts supply store, craft or hobby retailer. Exercise patience and a steady hand to preserve the quality of the paint.
Never use a scrubbing motion to clean the surface of a painting. This could cause irreversible damage. Work in a ventilated area with adequate light.