Got 2 question...

What is the best way to polish stainless steel headers ??

My passenger side header flare, is coming over, and rubbing my frame when Iaccelerate at times. The problem is the header flare is welded to the header, therefore I can't turn it, i'm stuck with it where it is. Would cutting a small part of the frame out where the flange is hitting hurt the frame any ?? Or is there anything else I can do ??? Thanks