Can't fix it if it'* inside. Unless you run a rod through it a few times to gut it. I had to replace to get through inspection here. Sounded like an old pinto anyway.

Running a rod through it can bite you in the *** sometimes. You don't want that debris running downstream. You end up with a rattling MUFFLER then. Don't do this unless you're trying to convince the wife into letting you put a performance exhaust on the car

Agree with Will. I replaced mine for emissions, but know people who have done it and still passed emissions. Good computer, I guess.