I heard using mineral spirits is a good way to clean bearings, but I also heard some can end up damaging them
Usually we do not clean them you simply pack new grease into them forcing the old crap out
WD40! Get a can and a small dish / bowl... Fill the bowl up 3/4 complete with this WD40 and enable the bearing soak in it over night. the subsequent morning you may pull them out and wipe them down... ultimately merely grease the bearings and positioned them lower back in.
Gasoline works good but be careful and rubber gloves might be a good idea.
The only way i can possibly see mineral spirits damaging a bearing when you clean it, is if you have rubber seals/protectors on the sides of the bearing, and if those are damaged you should replace the bearing. If it's just an open bearing, you can use, brake cleaner, lacquer thinner, diesel, gas or a degreaser to clean your bearings. Just make sure that whatever you use, the bearing is completely dry/free of it, before you repack the bearing, so it doesn't start breaking down the grease you just put in there. I like using brake cleaner and lacquer thinner because it dries fast and doesn't leave any residue.
