Rail Dust on black plastic wheel opening trim on Sierra

[Shredzy]

Have rail dust on the black plastic wheel-opening trim on my GMC Sierra.

 

Anyone have ideas on how to remove it? Haven't tried using the clay bar on it yet.

[cbrsilv15]

I think you answered your own question. Lol.

 

Clay bar will do the trick.

[newdude]

Rail dust? I'm going with brake dust. Try some all purpose cleaner and a stiff bristle brush.

[Shredzy]

Rail dust? I'm going with brake dust. Try some all purpose cleaner and a stiff bristle brush.

 

Definitely not brake dust.

 

Tried using detailing clay with no success.

[cbrsilv15]

Pics might help also.