Nobody will slag you off for asking this question again in the Mac II forum, so ask there.
Without a photo or detailed description, it is hard to give advice. I've rejuvenated Mac hardware that looked awful, but failed with hardware with apparently superficial damage. So there are no rules about appearances.
Any floppy disk drive with rust on the surface is an accident waiting to happen. As soon as the drive is introduced to a warm, arid environment, wee flakes of dust will separate from the major components and when they hit the drive head, it is "game over". Superficial rust might be treated using one of the rust inhibitors sold for cars or bikes, but rust elimination requires a complete disassembly, with aggressive cleaning before reassembly.