Both indoor and outdoor murals can become extremely dirty from soot, smoke, and oils from the hands of people that have touched them. The surface of murals and other pieces of art can be cleaned with an array of chemicals that restore the work to its original color. Each small section of paint is individually cleaned, which uplifts the original color to make the piece of art look brand new. Use small brushes, such as a baby toothbrush, and gently scrub the surface, concentrating on one small area at a time. Applying a few drops of dish detergent on a soft cloth can also be an effective way of surface cleaning a mural or painting.
The original artist also may have painted a varnish or topcoat over the artwork. Over time, this might darken or become yellowed. This topcoat can be softened by professionals and easily removed. A clear varnish can be applied that will protect the piece for many years without showing visible signs of aging. Apply your own varnish on a mural by using a spray. Use a light setting and broad, sweeping arm movements to completely and evenly cover the artwork. Goldenpaints.com provides purchasing information on clear varnishes.
Over time, paint can start to crack and flake off due to shrinkage, heat, humidity, and dampness. For murals painted with acrylic, cracking and loose paint chips can happen easily since it has a plastic base. Working on a space the size of postage stamp at a microscopic level, conservationists painstakingly attach adhesive to the back of each chip. Like a puzzle, the chip’s edges are fitted to its surrounding color. There are a few well-accepted adhesives used in the professional world, but sturgeon adhesive is often used. Sturgeon is actually membrane found in a fish’s bladder and has been used by artists dating back to ancient Egypt, according to Cool.conservation-us.org.
If a mural was painted on wood panels, the wood could possibly have bulges, ripples and other uneven spots that warp the painting. Conservationists are able to restore the panels to their original shape by steaming it like an article of clothing. The moisture allows a conservationist to straighten the soft wood. The panels dry and stiffen in between clamps and look almost new. In some extreme cases, however, the location of the mural might be too much for it to handle even after it is restored. At that point, the mural would have to be relocated for its conservation procedures and a new place to show it should be found.