There are several dry techniques for cleaning paper, including the use of white vinyl erasers and smoke sponges. Smoke sponges are made from vulcanized natural rubber, and are the same product used to clean smoke dust of walls after building fires. They come in large bricks, which we cut in to smaller pieces in the lab, and then gently rub on the surface of the paper.
This is a print I cleaned and re-framed. The glass was originally stained yellow in several areas, and the protective lining around the edge of the frame had split, which enabled insects to get inside. There were two dead silverfish pressed under the glass. I removed the print from the frame and took this picture.