Was that ingrained brake dust? or just tar marks?

Got one of the Megiuars kits from Halfords a couple of days ago to try - 2 cars to sell. The store in Castle Bromwich did not have them and didn't know what clay was, the store in Rugby had them.

Could be a busy weekend!

Was that ingrained brake dust? or just tar marks?

Judging by the colour the clay went I think it was tar. The wonder wheels wouldn't shift it at all. I use alloy wheel waxes and sealants quite regularly to prevent the brake dust bonding.

OTOH, the scratches in the wheels must have been caused by an abrasive in the clay which points to some brake dust welded onto the lacquer.