240Z: Got a new tool (Tumbler)

Yeah, you remember i tried to get those OEM screws cleaned from rust and old paint and stuff? nothing really worked, so i followed your inputs and bought myself a cheap stone-tumbler from ebay with some walnut-shell grain
hope this works. the walnut-shell’s came for free with the tumbler, so if this won’t work i might use some more specific stuff for cleaning metal. have to try it soon