Slamuth

+1. Ceramic coating is the best cleaner I ever used.

TheMule

Eagle One Etching Mag Cleaner and 0000 steel wool. This is an old tip I learned from my race mechanic.

READ THIS: Do not use this stuff while the tips are on the car, it has some sort of acid in it. I take the tips off and clean in the kitchen sink.

The tips inside and out will look like new. You can do both in less than an hour.

Quick Tip: Take a photo and measure from ground to tip to make re-installing easier.

Dadio

+1 Also makes them easier to clean in between bench polishing jobs. I can go 3-4 months of on car polishing with Blue Magic before I need to bench polish them.

r_32

Barkeepers Friend with super fine steel wool. Shines up like new.

StormRune

0000 (Quadruple-aught in detailer-speak) grade steel wool does the trick nicely and leaves no visible scratching... it is extremely fine. I takes me about 10 minutes of effort on each tip when I clean it and makes better progress than any chemical cleaner I've tried (but I haven't tried all of the above).

I learned about this when a BMW I had recently bought was showing an odd place in the paint and I took it back to the dealer. The BMW shop's detailer broke it out the 0000 steel wool and used it on the paint!

I also use it occasionally to clean gunk burned onto up on the porcelain burner pans on my cooktop (seems somewhat similar to the exhaust problem). Nothing else I ever tried could do this.

wbellinz

I typically use wd-40 to break down the carbon build up. It works surprisingly well and chances are you already have a can. I usually just use a paper towel, but fine steel wool will speed things up.

Domer911

+1 on blue magic metal polish

MessyMarvin

My car had the Optional Sport Tips, just like the Fabspeed all I have to do is wipe them down. They are expensive, but I bought CPO so I didn't really pay more for them. They look MUCH better also.