Mine have developed this yellowish rust, its not dust or dirt, it doesen't clean off:
http://i98.photobucket.com/albums/l2...gonpl/rust.jpg
I don't know if that should be any concern, I heard few people say thay are a bit low on quality............

 

It will polish off with some good stainless polish. Even stainless steel will show signs of rust. All of my stainless boat props have some surface rust after use.

 

They sell a rust remover at automotive stores. You should be able to get that surface rust off pretty easy.

 

There are different grades of stainless steel. 304 Stainless is a laser grade quality stainlesssteel that has a higher nickel content than other lesser grades such as 318. 304 stainless is almost virtually rust resistant. This is why you may find one brand of polished stainless exhaust much cheaper than others. There is a saving grace product for your boom tubes however. It is called Naval Jelly. This can be found at most hradware stores and marine shops. IT works wonders on removing rust from chrome, low grade stainless, alumninum, and even works well on magnesium alloy wheels. After cleanign and removing the rust or contamination from the exhaust tips, go back and polish with high quality brand of stainless polish. Hope this helps. Next time you purchase exhaust look a little closer atthe stainless steel makeup and ensure that they are made of 304 SS. My MBRP (steeda) exhaust are 304 SS and have been exposed daily driving including winter where they are not washed for weeks due to temps and all I have to do in the spring is polish the dullness out and they are good to go. A previous set made of 318 SS did surface rust after a long winter. Have doubts? Google 304 stainless.

 

mine does this as well, used a chrome polish and removed it easily.