While working at the Bell Museum years ago I was informed by John Jaros, then the preparator at that institution, that one of the most effective ways of cleaning mounted specimens that had become dusty was with bread. A loaf of sliced bread is cheap, already in usable sized pieces, will not blow arsenic dust or other harmful materials used in old mounts all over, and is easily obtained. Bread has just the right amount of moisture in it to be effective at picking up the dust on fur and feathers yet not enough so that the moisture from the bread causes a problem. Simply buy yourself a loaf of Wonder Bread and proceed to wipe (gently) the dust and grime off of your mounts. This is probably the best way to clean mounts and perhaps the best use ever found for Wonder Bread as well.