Unfortunately media selection is almost entirely based on the type of results you want in the finish vs how easy it is to remove from parts.

Corn cob is great for polishing to a decent shine, walnut is great for removing dirt and even paint but leaves a dull finish. I almost always have to use a dental pic to clean out little parts but can’t say I’ve ever hurt myself with it to be an issue. I’ve also put tumbled parts in a small Tupperware after separating and shake it around in the container and it breaks lots of the media free from tight places.

Bayoubilly was right about the buffing wheel, but it’s tedious and sometimes dangerous for small parts.. I use the buffing wheel and a green polish bar for most parts.

You could try wet tumbling with stainless steel, I’ve done this for brass and other metal parts for gunsmithing but not tried for pinball.