Gell type paint remover like Navel Jelly and a power washer. That is what I was told by the powder coater I was going to have repaint my car's wheels. Bead blasting may not be the best solution unless you get the right media. If you go that route, make sure you consult someone who knows what they are talking about. Using a hard / agressive media can take away aluminum faster than paint sometimes. I would think something like walnut shells would be better.