Just get some toilet bowl cleaner. The Works or LymeAway both work great. They also work great to clean your hull to get the yellowing off and also your props. Your working way to hard to keep your tips clean.

There's nothing to prevent them from doing that, you have to clean them after every use. White vinager after each use will keep them looking like new. If you don't clean them every time it gets much harder and have to use some of the stronger chemicals like clr, toilet bowl cleaner or acid.

Bartenders keep liquid. Haven't tried the spray yet. It's cheap, safe and it works very well. I also use it on the hull since it doesn't degrade the gel and attack stainless over time like muratic or hydrochloric acid either. Oxalic acid is the active ingredient.

Like others have said, you need to clean exhaust tips after every use.

http://www.barkeepersfriend.com/

http://en.wikipedia.org/wiki/Oxalic_acid

I find just dipping aluminum foil in water will make them look like new again. Just make sure you polish with the shiner side. I have those same tips and it worked great.

Its local to me so its easier but I had one of my mufflers done with Durafortress to see how it works... it cleans up in about half the time and without any harsh chemicals
Did my aluminum tabs with it after I had em polished the stuff really works. still looks polished.

http://www.durafortress.com/

Thanks for all the replies! I tried white vinegar and CLR, both worked really well. Almost effortless. Can't stand the smell vinegar so I'll stick with CLR. I'll try some of the other suggestions next season.

The vinegar is really cheap though. I buy it by the gallon at Costco.

BioKleen Fiberglass cleaner works wonders on exhaust tips

I spray mine with vinegar after every time out. Doesn't work as fast as the caustic cleaners, but gets the job done without damaging anything..

CLR works good for this. Mine get nasty with the stellings dry tails. If out of CLR mothers alum polish works too. Just takes a bit more elbow grease. No wax out there prevents this. Tried it all....

http://s1319.photobucket.com/user/Lu...tml?sort=3&o=3