RolanTHUNDER

After cleaning it thoroughly I'd recommend polishing with Autosol. I used that on my Vortech SC and it came out beautifully! Granted it doesn't have a burnt section like your exhaust but I doubt the Autosol will remove that. Then again, don't hold me to this lol

Classic JDM

Bar Keepers Friend will have it looking like new in no time! This stuff is amazing. They sell it at Wally World.

choppstixxx

Clay bar def., it shouldn't remove the "burnt" look and will remove the tar safely.

toztigger

on my evo i use to use normal dish washing detergent and dish sponge, takes some work , make sure you use the soft side not the green abrassive side unless you want swirls and scratches, just keep at it till it comes off