I use MEK, (methyl ethyl ketone), rather than Acetone to clean up my brushes, cups, and tools after a lay-up, I also use it to thin the resin, or top coat to brush on, or spray, in my opinion, it works better than Acetone, much faster, and Yes, as with Acetone, or any other type of petrolem product, it is very combustable, and is a skin and lung irritant, I wear surgical gloves when I use it, and ofter a resperated mask, and I do my cleaning and mixing with it in another room, not in the same room with a flame producing heater. The MEKP (methyl ethyl ketone peroxide) I use to activate the resin (kick) and I'll mix it with the resin to a ratio of about 1 1/2 ounce to a gallon, or a more for cooler temperature.