.........the cleaner is ZEP industrial purple....
Good.......I don't feel like such an idiot now....I'm not the only one who has done this......
only I ruined a CUSTOMERS expensive bicycle parts, not a bunch of my own pistons............
DON'T try to remove it...That stuff actually stripped old anodizing off and stained
the aluminum very deeply on my little accident.
You would have to take quite a bit of material off to actually remove the black coloring.
Clean them off and polish 'em up, but try not to actually remove any material.
Use really fine steel wool to polish them out, but don't get carried away.