Over time, the varnish that some artists use to protect the surface of an oil painting can deteriorate. It may crack, whiten or yellow. In the case of yellowing, the discoloration obscures the painting's original details and affects the overall tone. White and cream tones turn yellow, while blues turn green. Cleaning the yellowed varnish is a touchy process, but it can dramatically change the appearance of the oil painting.
Instructions
Freshening up Your Art Collection
1. Consider the sentimental and financial value of the oil painting. If the work has been passed down in the family for generations or has been appraised at a high value, it is better to leave intensive cleaning to the experts. The most you should attempt is a regular, gentle dusting to remove surface dirt and cobwebs. Ask a gallery owner, museum curator or antique shop proprietor for recommendations of professional cleaners who restore oil paintings.
2. Remove the oil painting from the wall. You may opt to remove the painting from its frame as well. Tap the painting along its edges to shake away any surface dirt or dust. Use a very soft paintbrush or a baby toothbrush to brush away dust that has attached itself to the painting's surface. Do not attempt to brush sticky sections of the painting.
3. Examine the state of the varnish. Now that surface dirt has been removed, you can determine if the varnish is too yellowed, or if the painting has just taken on a pleasing patina that comes with time and age. Conservators call this effect the "old master's glow" because an aged oil painting has its particular aesthetic value that some argue should not be removed. Removing the final coat of varnish on an oil painting is an irreversible process that fundamentally changes the painting.
4. Use a liquid varnish remover to clean overly yellowed varnish from an oil painting. Check with an art supply store to find the best brand for your job. Test a small corner of the painting by dabbing at it with a cotton swab soaked in varnish remover. Use cotton swabs to remove the yellow varnish, with a rolling motion rather than patting. Do not press too hard against the canvas. Avoid letting the emulsion pool up and saturate the canvas. Check the swabs to ensure that you are removing only the topmost layer of varnish and none of the paint. You should see the composition brighten as you apply the emulsion.
5. Add finishing touches. You may opt to revarnish the painting to protect the surface. Dust and polish wood frames. Clean mats and glass. Use a vacuum and mop to clean the area where you will hang the painting. Maintain the cleanliness of your oil painting by keeping the area as free of dust particles as possible.
