I noticed some white what thought was mold on some of my screwdrivers Craftsman, Snap-On and Stanley. I cleaned a few of them up but it returned so I looked it up on the inter-web and found a lot of results for "mold" and "stinky screwdrivers" some are pasted below. The good thing is that Snap-On replaced them and so has Sears so far and Craftsman screwdrivers are still made in the USA. ............................................. I have a white substance that seems to be growing on the plastic screwdriver handles. Does not appear on metal tools. Anybody know what this is? More importantly, how to get rid of it? Answers: It is the plastic in the handles breaking down, and is characteristic of the plastic, cellulose acetate butyrate. High temperatures make it worse, but it will show up at room temperature given time. Butyric acid. Spoiled butter smell. Puke, especially baby puke. Butyric acid is common in butter, only it is combined with glycerol in triglycerides. When it decomposes, the butric acid is released. Same in the handles. Old age , I had a bunch of tools my Dad bought 50 years ago but no screw drivers except the old wooden handle ones , some of mine that are 30 years old are doing that too . In a few more years the handles will dissinegrate . Quality makes no difference , the Snap On screwdrivers do it too . My black handled Snap-On screw drivers from the 80's started sweating while resting in the tool box. When dry the handles developed a white residue. Easy fix for me was to have my Snap-On rep replace all of my handles. It could also be from me wiping them down with solvent or parts wash to remove the oily residue accumulation while wrenching. I think it is the plastic breaking down.