Hello, found this old thread and bought some steel wire brushes as suggested but before proceeding I just want to double check, and triple check, that this isn't going to grind the threads into oblivion. I would rather try brass wire brushes and maybe I will but I could only find the disc type, these pipe cleaning brushes, I'm guessing for welding, seem perfect for this job (38mm and 28mm) except that they might be way too brutal, they are very stiff and very mean looking. Plan is to spray in some light oil, of course set the drill on low speed, give it just a few spins, and check the progress, slow and careful (maybe avoid back and forth motion?) but, honestly these brushes look like they'll grind the threads off in an instant. It's for a nice and otherwise clean Moser Deda Zero Tre frame, that I don't want to wreck.

BTW, the issue is rust in addition to hard grease, and crud, would kerosene be better than light oil? I also have a round p-tex brush for use with a drill, maybe I should try that first?

Maybe someone will chime in? All opinions and dire warnings welcome.