In my manual, it says to take out the plug on the muffler once in awhile, and blow out the carbon build up. I tried to get that plug out, and it is like frozon onto the muffler. I thought I'd snap my wrench off trying to remove it. Any suggestions on how to lossen that plug ? Also, what can I use to make the black rubber part of the fenders look new again, or at least better? I've tried Mothers Black to Black, and black tire renew without any positive effect.