Phosphoric acid ruined a chrome header pipe of mine. I didn't soak it overnight or anything like that. I just made an aluminum foil boat & rotated the exhaust pipe in the solution for a few minutes. Something I learned was that if the exhaust pipes are rusty, try running the motorcycle to full operating temps before using any chemicals >> the rust pretty much burned off the other 3 pipes & the chrome looked fine other than the exhaust blueing & minor pitting. This was a junk exhaust system in poor condition, so ruining that one pipe was no big deal.
Rust treatment & prevention. On the back side of chrome steel parts I clean off as much rust as possible, then use a rust converter spray from the auto parts store, then top coat with a spray paint or spray coating. On the muffler heat shields I use-b-que grill paint. On the tail light bracket, headlight bucket & other similar parts, silver wheel paint is good. For the fenders I use a rubberized undercoating. I hate rust, so just about every chrome steel part on my motorcycle has been treated. I think the only thing I haven't done is the chrome chain guard, but it's usually coated in chain sling, so it's automatically protected. hee.
Rustoleum silver bar-b-que grill paint. Cleaned insides of muffler system by various means & used EvapoRust,
then painted insides & exterior manifold section w bbq paint. Paint still intact.