just wanna no how to get my rocker cover crome and shining like some of the boys here

Get a comfortable chair some sandpaper, metal polish and something decent to watch while doing you'll be there for a few ours.
You may want to grab a replacement cover down the wreckers to use.

http://www.fordmods.com/exterior-modifications-f15/tech-diy-polishing-aluminum-other-bits-t19203.html

pictures dont work anymore, but text should get you there, there are 1000's of guides by searching google, from memory calaisturbo.com had a good one.

good luck will take many hours, and your missus will wonder why youve been grunting the the garage for hours and come back with a really sore right arm

Gonna take some time, why not just paint it?

If you are lazy and want the chrome look call All Surface Chrome 0407 593 687. They do a painted chrome finish which looks awesome. If you are not lazy polish it by hand. i spend 16 hours on one getting it to a mirror it is worth the effort. The only problem is that you need to give it a light hand polish at least every second week to keep the mirror shine alive it is easier if you stay on top of it rather than let it die then try to fix it! Best bang for buck polish for raw metal surfaces is Brite Shine, it is a little yellow tin you can get it at autobarn etc... The polish is abrasive free so it does not cut the surface it just restores and protects the established finish. But if you really want it to slap you in the face use Red Rouge, face make up red rouge that women use! That is the final step in polishing metal surfaces to a true mirror. But if you are going to use rouge you need to have a surface with absolutly no scratches so you would need to be working your way through all the different polishing greases and wheels first.

Autosol is another polish which works quite well. You're gonna be in for quite a task though .

Use paint stripper to remove any painted coating (if any) on the rocker cover first. Then start sanding and filing out all the imperfections in the casting i.e pitting, scratches, burrs etc. You'll probably wanna work your way up and sandpaper grits from something course like 320 grit or lower to something very smooth like 1200 or 1500 grit, so that when it comes to polishing you wont have as many scuffs that need to be worked out and will bring out a nice shine.

Then its up to you whether or not you want to seal the polished surface to stop any oxidation and fading over time. Only downside to sealing the polish is it may take some of the shine out of the polish depending on what you use, eg. clearcoat

if it was me i would get it soda blasted or sand blasted to remove the paint and bring it back to bare metal to help with the sandpapering and polishing.