Salt and Vinegar works good, according to this Corvette Owners Forum. The only caution is sealing the metal as soon as it is dried off. Rust Reformer from Rustoleum/Tremclad or POR's Metal-Ready Phosphate. The Metal-Ready does remove rust too, but it's like 40 times more in price for the same quantity ($86 per gallon, $22 per quart). http://forums.corvetteforum.com/showthread.php?t=1485242 The Table Salt with Vinegar makes a mild Hydrochloric acid. Then one sheetmetal site also offers a nice, cheap way to seal off the metal after treatment with Arm and Hammer WASHING SODA, not baking soda. http://www.metalmeet.com/forum/showthread.php?p=89414 I'm on my second quart of Metal Ready, and figured it was time to find a way to clean off the Door Hinges and inside the doors. Vinegar on a damp cloth works for surface rust.
I just used it on all my door-hinges! Four tablespoons of salt (could have used more) to 6 litres (1.5 US Gallons) of Heinz white vinegar. 24 hours later: Like a new dime! Even helped soften the original paint! I used Rustoleum's Rust Reformer then 2 rattlecan coats of my final color. I've got the old emergency brake cable system from the donor car in the same original pail of the solution soaking for 2 days to free up the pedal assembly and it's cleaning up nice too! I'll do the window winders next. I bought the name brand because theirs was always the best, and because it was at half-price (springtime pickling season, right!) Well the salt makes a safe (for our delicate skin) hydrochloric acid (ionized table salt) with vinegar (acetic acid), it works wonders!
