I have a set of 86 T-type wheel that have picked up some black specs on one wheel in the rough cast portion. Looks kind of like a bad grease seal slung some stuff out, but it’s more presistent. I can get it off by scrubbing with a bronze brisle brush and wheel cleaner but it’s a big task. I’m open to suggestions about how to clean them up easier, possible a light bead blast. I’m polishing the ribs anyeay so any minor dulling of the ribs would be OK.