Mounts can cause stains on the paper or they can be too 'fixed' and can cause the paper to tear, as in this example.
This drawing had a tear within the right margin. By releasing the drawing from its mount the sheet is not within danger of tearing. Asian mounting methods have mounts made of weaker paper which tears when strained, rather than the work of art.
This image has been photographed on a light table so as to capture the laid paper and the watermarks.
This example shows a very disfigured drawing of a man and ends with a portrait that can be re appreciated.
This drawing had been folded up as a letter. Dust and surface dirt had masked the French text along the bottom margin and the sky area.
After treatment the text can now be read and the surface dirt has been vastly reduced so that the charm of the pencil drawing is easily seen.
The result is that you have a detailed drawing of the Bay of Odessa revived.