I use the magnet wand as well. The thing is a great tool for working on pins and retrieving hardware from media, cabinets, etc...its indispensable.
I've use reptile bedding with great results. Its finer and works on smaller pieces better.
I've used rice as well. It is actually good at holding a polish if using one, but its softer so really only good for finish polishing.
I used Lymans walnut substitute. It only worked OK and tended to leave the redish dust everywhere.