i mixed up 5 gallons. i put in a really nasty rusty 383-4 intake that sat outside for a really long time. it came out awsome, but i didnt want to remove it until i figured out what would work to nuetralize it. it sat in the tote a few days i put some brackets in it yesterday and the stuff is dead. didnt touch the rust on the brackets. so yeah its cheap to make but, 20 bucks to derust and intake manifold, im not sure if its really worth it. evaporust seems to last longer.