Has anyone stripprd the black paint off then polished out a mopar performance air clean lid? The lid that says mopar performance on it and finned.What grit of sand paper did you start with and end with?

No one has?this could be polished?

Try it yourself on the underside.

Aren't they powder coated ?

Can't you strip the power coat off?

Powder coat is very hard to get off. Stripper doesn't work well and it takes forever to sand blast because it mostly just bounce's off.

Ok what about brake fluid?that eats through anything

I didn't try it but I'm guessing it might just discolor it.

I was waiting for someone with lots of experience to chime in, but since you haven't gotten the advice you're looking for yet:
I've done a little bit of aluminum polishing, but am no way an expert. Watch a couple youtube videos on both removing powder coating and sand polishing aluminum. When I polish, I get the paper (eventually) down to 2,000 grit before I start polishing. The fins on that lid will (obviously) be a bit tough to get into the crevices, but stick with it. It's not a tough job, but somewhat time consuming. The more patience you have, the better the end product will be. Give it a go...you'll be glad you did.
Oh, and start with the least aggressive paper that removes the big stuff. You're eventually gonna have to sand those scratches out. Don't forget to show us your end product!

Powder coat places should have a chemical dip to remove it. Not all aluminum polishes out the same either so it may not shine up as nice as you expect it to. Been there, done that with numerous car and bike parts over the years.

Prismatic Powders sells a chrome powder coat that may be better and more uniform than all the sanding and polishing work. You can buy a color swatch from them to see what it looks like. Typically powder coat places don't stock a ton of unique colors, and they can get crabby when asked to custom stuff in small batches. If this is the case then you can order the bags of it thru Prismatic yourself, and then give it to the applicator, which is what I have been doing.

https://www.prismaticpowders.com/shop/powder-coating-colors/UMS-10671/super-chrome-plus

A normal 5 gallon free paint paddle. Wrapped in sticky 180 grit (long board sandpaper for body work)
That will be best bet inside the ribs. If not working go to 80.
Followed by 180 or 220. Then wet 400, 600, 1000
Then black emery, gray emery, white rouge, blue or green rouge.
On this 180 was going to not cut it. So had to go 80-180
In the past have found in some cases black was done to cover the bem and better quality oned were used on the polished version's.

i was waiting for you to chime in and show a before/after picture, plus tell what it takes to get there.
every time i see your work, i get excited, then tired, so i haft'a take a nap ............
you do GREAT work sir ! i respect that endlessly !

Since you are new to it and will have limited things to sand with and get in the tight spaces.
My advise is the leave the center section alone and shoot that part silver. Tape the polished fin tops up and shoot it with Ralley wheel spray bomb or something close in light sliver will do. Talking about the part highlighted
If you don't mess with that part it will look better silver than half way done.
It will be fne with just the top of the logo block sanded and polished, and the rest polished.
If you look lots of polished vavle covers are done that way.
You can sand right up to the shaded part easy with a paint paddle wrapped in sand paper down in the ribs.

Thanks for the info and sayin how to do it