Go to a farm supply store like Tractor Supply or your local farmers' co-op and get a couple of gallons of molasses cattle feed supplement. Submerge the parts and wait a few days. A hot water rinse will clean up the now rust-free parts, and you can seal up the dip pan and reuse the stuff repeatedly. The ratio of molasses to water is about 9:1. Inexpensive, but time consuming- - - -maybe a month or more to displace all the rust if it's something like a bumper bracket or a backing plate.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!