In this studio conservators restore the surface of paintings to a condition that most closely resembles an earlier unaltered or undamaged state. The two most common procedures that take place here are cleaning and inpainting. During cleaning, conservators carefully remove layers of accumulated grime; darkened varnish; and old, discolored retouching from the surface of paintings. To restore areas of lost paint, conservators fill the areas of loss with gesso, and inpaint them to match surrounding areas of original paint. They use easily reversible materials and take great care not to cover any of the original paint that had been applied by the artist.