i just got a whole flowmaster system put on my truck last week and already there's rust forming in the inside of the tips. what do i use to clean it out and how can i prevent that? it looks god-awful!

 

theres a type spray you can buy that you can spraypaint the inside of the tip so that it looks brand new for a long time. Someone will more than likely post something about it in this thread.
*Tip---> to keep outsides from rusting, go to autozone or walmart and buy some Turtle Wax Chrome Polish. Little white bottle with a red cap. Use it on your tips once every week or two to ensure they dont rust. My chrome tips have been through 3 winters with some salt, etc and only a very small spot on the very edge-very minor. The stuff pays off !
-Patrick

 

Just get some BBQ 2000 degree paint from home depot and sray it in there.

 

one of those foam trim brushes and tie it to a stick and you'll be able to coat the insides with out a big mess....tip;next time go stainless