How do you clean up a gas spill in a garage?

Get a bag of cheap, but absorbent cat litter to soak the liquid oil. Scoop it up and put into a double trash bag (so it doesn't leak in you car) and take it to a parts store or an auto service center and see if they will put it with their oil to be recycled. The oil stain on the concrete can be cleaned with Purple Power and a scrub brush, and the residue can be hosed down and flushed outside or into a city storm drain (the water deludes the chemicals enough, so they aren't harmful).