I'm told a lot of people like to blast with soda (baking soda) because it's water soluble and you then don't have to worry about little bits of blasting media getting stuck in crevices.
Also, when powdercoating metals that are exposed to oils you want to make sure that they're throughly cleaned and baked to encourage the metal to out-gas as much as possible before coating. If you don't, the coating may not stick.
