i use paint thinner because its real cheap at the harware store . i get a oil drain pan and take the silencer apart and let it soak in the pan a little bit . for most part the gunk will come off with little a little scrubing and let dry , repack and put back together . just do outside in a well venilated area , i have never heard of using oven cleaner .
If you can live with the noise, and I can, what harm could there be in not re-installing the packing; just let'er come straight out.The back pressure isn't needed for anything is it; I mean to help it run in certain conditions.Seems like the quicker you get the exhaust out the better right?Plus it helps me pretend I'm on a kx-250 with the throttle pinned and still in control LOL.
Where I live we don't have riding areas, you just go where-ever you can find a place, mostly forestry owned land by companies and there's probably not more than 20 dirt bikes running in my county anyway.We only shut down for hunting season.