Acetone + acid + time ==> a lot of crap + H2O
Acetone in the presence of acid self condenses to diacetone, phorone, mesytilene and a lot of other smelly and ugly looking stuff. Never let an acidic solution of acetone stand for more than half an hour at ambient temperature.
Something similar happens when you put a base in acetone only the product is mainly diacetone alcohol.