Mud in exhaust pipe on my ATV?

[Justin]

Going mud boggin. I've never really had too much of a problem with this, but now i am wondering...
I recently took my muffler off my 4wheeler. I go muddin alot. What happens when mud gets in the muffler? I know it spits it out but im sure it cant get ALL of it out, especially it being at an incline coming out. And now that there is no muffler, it has an easier route to my engine. Anyone want to help?