How do you restore the aluminium end of the fins on a Night Train black engine ?

I tried wd-40 and a brillo pad, but that doesn't clean everything. I tried sandpaper but am affraid to damage something.
I checked but did not find a previous post on this, so your thanks for your input.

 

i've had problems with this, too.. the only thing i've found that works decently enough is a bottle of Simple green spray, and a green scrub pad.. but the fins aren't smooth, so i end up tearing bits of the scrub pad here and there, or slip and tear a knuckle open

 

S100 makes a engine restorer or brightener... i used it on both my bikes,,, the 2002 is blacked out and it brings back the black to the wrinkled finish...

 

hd and s100 make an engine brightener. I have the hd one and it helps but is no cure...

 

There are several safe citrus based Aluminum brighteners that can be used.

 

A closer look shows oxydation of some sort.
Torn brillo pad and knuckles: check...
s100 on black part: check (looks good)
about to cut lemon in half and rub it agains fins... what's that ??? ok, I'll get some citrus alu cleaner and give it a try. Thanks!
... and if that's what misbehave used on his bike, according to the pic, i'll give it a shot for sure. engine looks quite clean !

 

What's the answer to cleaning the gray on fxst?

 

paint it black

 

For the Black Pig Spit is lower cost than HD or S100 engine brite.
On the exposed fins some elbow grease and a scrubber pad will shine them up.

 

I pulled mine and had them PC'd Black. now no more worries about keeping the fins shiney and while they were off it was the perfect opprotunity for engine upgrades ; )