--- der Mouse <mouse at rodents.montreal.qc.ca> wrote: Yes, acetone also disolves polystyrene. Some uni/college student visited the lab where I work (I'm a technician, not a chemist, and my chemical knowledge is limited other than what I have learnt at work over the last 8 years) a few years ago and decided to clean the runners on the plastic slidey doors (do they have a proper name?) on the side of one of the balances. Naturally, as someone else mentioned, the acetone turned the plastic into mush and the door become tough to open, often sticking, instead of being smooth and easy. Generally, we use acetone to clean marker pen off of glass equipment (eg. volumetric flasks) and for cleaning oil/grease out of the metal cups (we test for fat/oil/grease content in the waste water from factories that send there waste into our* sewers) Getting it back on topic... is there an easy was to determine which computers/peripherals can be cleaned safely with acetone, or similar substances? Regards, Andrew D. Burton aliensrcooluk at yahoo.co.uk * I work for a well known UK water company, mainly b ased in East Anglia.