The KR mufflers (Ford Racing PN M-5230-S) are pretty ratty looking right out of the box with lots of residue on both ends - probably a byproduct of welding. A TS member previously wrote about cleaning the ends with an Aluminum polish so I decided to give it a try. I used Mothers Mag and Aluminum polish and cleaned off the ends. Real easy process and it makes the mufflers look way better. I also heard from a reliable source that windex works pretty good too.