A BUDDY OF MINE WANTED ME TO TRY THIS. IT IS GREAT I GOT 4QT. PUT IN A 5GAL. BUCKET. DROPPED IN A RUSTY TANK OVER NIGHT IT CAME OUT SHINY CLEAN. YOU CAN PUT YOUR HANDS IN IT DOSE NOTHING TO THEM. IT WAS ABOUT $ 9 A QT. AM NOT SURE HOW LONG IT WELL KEEP EATING RUST BUT ITS STILL GOING AFTER A WEEK LOOK IT UP AND READ ABOUT IT GOOD STUFF :thumbsup::thumbsup: