Gotta really clean it up afterwards, main reason is you may not get all the material out of the nooks and crannys and it would come back to haunt you later on. When I did my auburn and had to grind off part of the webing inside we stuffed rags in the enterances to the axle tubes. I would also use a really big swab and clean the axle tubes out like you were cleaning a cannon barrel, one push from ends to center, remove rag and dont pull it back thru. I'd also fill any screw and bolt holes to keep the medium out of them. I think I would consider using glass or other organic medium first.
Just curious, why blast it, is it extremely rusty ? If it's just grunged up I'd use a good solvent and stiff brushes, let it soak for a few hours.