The best advice I ever got about this (and it works) is, if you get your rust grinder in hand, and then position yourself so that your face (viewpoint) is as close to the rusty part as possible without actually clipping through it, then activate the grinder, it'll take the rust right off.
Not saying that this isn't a little frustrating and not how most users would expect this to work (hence still a bug) but this might help you in the short term.