Two brands of rubber so-called chemical sponges commonly used to clean soot off walls and various surfaces after a fire were analyzed by Fourier transform infrared spectroscopy and scanning electron microscopy with x-ray energy spectrometry (SEM/XES) at the Canadian Conservation Institute. Both the Wallmaster Chemical Sponge and the Quality Rubber Sponge were made of vulcanized cis-1,4-polyisoprene with a calcium carbonate filler, less than 1% oil and traces of sulfur, aluminum, silicium, iron, and zinc. These results are compared in a table to the composition of other similar sponges, absorbent rubber (Groomstick® molecular trap) and eraser products analyzed several years ago. The chemical sponges degrade significantly with time; a sample after two years became hard and crusty. The conclusion is that chemical sponges can be used cautiously to remove soot on artifacts provided that great care is taken to remove residues. The sponges do not contain the more abrasive silicates found in some eraser products proscribed for conservation use. Abrasiveness is a concern, as the technique of dragging is harsher than rolling. The sponges have been found effective to clean large flat surfaces but not as effective as eraser powders or Groomstick® for small or uneven surfaces.