Zep Driveway Cleaner contains sodium hydroxide aka lye. Be very careful using it on anything made from aluminum. May cause it to turn black if not washed off soon enough after it does it's work. Will EAT the whole thing if left in it for a long period of time.

Zep C-L-R contains Urea hydrochloride which is a salt formed from the simple mixture of urea with hydrochloric acid. Urea is the major chemical in p i s s, added to hydrochloric acid.

Not that I wouldn't use either of those chemicals, but I wouldn't drop a carb in either of them and walk away.