just cleaned the stains from my wifes nightster tonight. i didn't take before and after pics but the stains on the grey were real bad. hit something on the road or oil splattered in the hot motor. also had a spot under the timer cover. I tried everything, wd-40, simple green, flitz, gasoline, brake cleaner, soap. NOTHING WORKED. i read on an old post about CAMEO aluminum and stainless powder cleaner.

took a bowl and added the powder along with water to make a paste. i used a tooth brush on the wet grey right side cover and front pulley guard. i had to scrub like a bitch but 75% of it came off. i re-wetted the cover and scrubbed for another 5 minutes. now its about 85% gone. I will continue a few times tomorrow and will let all of you know how it turns out.
this is the only thing i found so far that works.
good luck.

 

Keep thread alive.

I haven't found anything (WD, polishes, toothpaste, S100, Simple Green, Soap, other - none have worked)

Have not tried Magic Eraser.

So what definitifinly cleans the grey?

 

Be aware that "magic" erasers are nothing more than very fine sandpaper.

 

Gunk engine degreaser and a fine bristle scrub brush spray the degreaser on let it set for 10-15 mins then scrub, then spray off engine, use leaf blower to dry water off then spray with HD engine Brite this will make it shine and also put a protective coat over the engine to make it easier to clean next time.

 

Spray n' Wash

 

wd-40!