belkins

Muriatic acid. Guaranteed to get rid of rust. It's usually sold in the paint supply area at Home Depot or Lowes (they may have it outside because it's a highly caustic chemical).

I CANNOT EMPHASIZE ENOUGH HOW CAREFUL YOU HAVE TO BE WITH THIS STUFF!!!

Be in the open air and wear gloves and do not splash it on yourself. If you do get it on yourself it stings, just wash it off immediately.

It's very cheap, about $4 a gallon. It's used for etching concrete prior to painting it or sealing it with some type of epoxy paint.

You put the rusted tools in it and the acid will bubble and sizzle for a few seconds until the rust is all gone. It strips it down to bare metal so you need to wash off the parts and oil them IMMEDIATELY or they will flash rust.

I was amazed how well this stuff worked when I first used it on a friend's recommendation.

Do not put chrome or brass in it. There will literally be nothing left!