I would avoid the wire brush like the plague ....I have seen way too many tools , guns, knives and bullet moulds ruined with a wire brush.
I don't know about chemicals or bead blasting....I would do it old school , by hand with black wet or dry paper and oil , back the paper for the flats , go slow start with #220 or#320 at first, working through the finer grits and finish with #400 or #600.
3M also makes sanding sponges which works great for curved surfaces.
This may not be the fastest way but you want run the risk of a long soak in a chemical dissolving the grips.
The type of paint will dictate what will remove it. If you do try paint remover or stripper test a small part of the grip to see if they are affected by it. It appears the scales can be removed...that's good !
Chances are a combination of a quick application of paint stripper , removed as soon as the paint is softened, and the sanding by hand will get the deed done safely...good luck,
Gary