well i was cleaning my car and cleaned my muffler last. anyways...as i was taking out the silencer ( i like the sound but not too loud ) i noticed these little solid particles inside the tip. they look like those little rocks you see on roofing shingles. I had the muffler for about a month now. i never noticed anything when i had the stock muffler. it probably never get out since the stock isn't straight through design. well here's my questions.
1) what are these little 'rocks?'
2)where are they coming from?

i currently have a magnaflow. any ideas? thanks in advance

 

its probably carbon that has hardened in the exhaust and come loose

 

i thought carbon deposits are black? only some are black, most of there are like rusty colored. whatever the case...hope this isn't an indication of something bad.

 

it's probably rust out of the pipes upstream... like right behind your cat where it's really hot and always rusts.

I would check the system for any spots of heavy rust and either have it fixed or replaced.

 

Take a rubber mallet and lightly tape the entire exhaust system starting from the y-pipe back. Use your hand if the mallet isn't available. Could it possibly be the internals of your cat starting to break apart? Besides the muffler, is your exhaust stock/original (y-pipe, cat, resonator, piping, etc) How many miles you have on the exhaust?

 

yea my exhaust is still stock besides the muffler. i got a litle over 140k on the car right now. not sure if the exhaust was ever replaced.