question, I own a home and just started renting a room out to a friend. I have been helping him sell some gadgets online (he makes them himself). he purchased hard plastic tubing to make the items (it's pretty small tubing). he buys the tubing in bulk. he uses pure acetone to remove some manufacturing numbers that are stamped on one side of the tubing. he uses a cotton swab and dips it in a pint bottle of pure acetone and then uses the swab to blot out the stamped number. I think that's great. however, he's doing it on my living room floor which concerns me. and what concerns me even more, it he spreads out some newspapers to work on and lets the area of the plastic tube dry (the area where he blotted out the stamped number). is this safe? sorta safe? or not safe at all? and when I say safe, I mean safe on the living room floor of someone's home. I really thought laying newspapers under it is a stupid idea. I know nothing about pure acetone other that I read it is flammable. my roomate just told me it was fingernail polish remover (which women use all the time in the house) so it should be no big deal to use in the house. all responses are much appreciated. I asked him to take it outside, but he told me he would be extra careful. it's starting to get cold where I live (that may be one of the reasons he doesn't want to take it outside).

thanks