I have samson fishtail straight pipes. They also blue at the right exhaust. I bought a can of blue job, and it works just fine. It does take a lot of elbow grease, but once done, they look new again. I just did mine last month, for the second time. Someone said to try some rtv high heat silicon at the slip on junction. I think I am going to try that the next time I get down to clean them. It might help. Also, since my pipes do not have a baffle, and are straight, I was thinking of adding a set of heat shields, and butt them up to the stock heat shields. Just a thought.