odor in car

I recently had a new alternator installed in my '96 Riviera. Right after this a strong smell of acetone was present. Then mechanic put in new battery and new supercharger. He said the old battery was the cause of the smell. It has been two weeks now and the smell is getting stronger and seems to be a lot of steam or vapors coming out of exhaust when car is ideling. Anyone know what this smell could be. Some people say it smells sweet like a peach-- to me it smells like nail polish remover.