For really aggressive rust removal, use Muratic acid (technical grade hydrochloric HCl) mixed with water. The stuff used to clean up excess mortar after a brick-laying job. Just don't walk away for very long if you want any parts left! Those bubbles are Hydrogen gas- - - - -no smoking or open flames!
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!