Ive got a barrel that has a lot of rust,,I have heard folks on here use Evaporust,,,where do u get it,,ive been to all the big box stores around here and hardware stores and no one seems to carry it,,ive seen a lot of other products,,one is called Krud Kutter,,water based, will this work as well,,also I have some Ospho but not sure I want to put this down the barrel