If you blast them, they will not have a polished look without some extra work. It will give you a good place to start so you can repolish them, but simply blasting them will leave a dull raw aluminum look.
Another option you might want to consider is a good paint stripper. It'll probably take multiple applications to get it all off and it'll definatly be more work to get it off, but it will not hurt whatever polished material you have below the paint and old clear.
What size wheel are you looking for? It might be easier to just sell what you have and pick up a different set on craigslist.