Sandblasting

1. Silica sand (play sand) works good but is dangerous. Use with extreme caution under proper conditions.
2. Glass bead and crushed glass also contains silica but is safe though with proper protections.
(It's that chemistry thing).
3. Then there is aluminum oxide.
4. Delicate parts like carb bodies can benefit from baking soda.
5. Walnuts?
That's all I got.