I used to use a Haybuster 256+2, now use a Haybuster 2650. 

On the older 256+2, I done the fire thing and running the pto to eliminate the net and twine from the rotor, not too bad of a solution to the problem. 

On the 2650, with the much easier access to the rotor through the side rotor door, I use a utility knife with a double-ended HOOK blade. 

I clean the net off about once every 50-100 bales, depending on the weather.  The utility knike I use has tooless blade change, and that's pretty important since the blade needs to be SHARP to be effective and I usually cut from one end to the middle, change ends with the blade, and finish cutting the rest with the other sharp half of the blade then dispose of that blade (buy the blades in a 50 or 100 pack and leave them in the tractor, they're handy for any problems baling too).   

I usually pile the netting in a gate driveway or the middle of a dirt road intersection and light on fire and let it burn.  It's pretty nasty smelling stuff if you burn it too close to the shop, and it'll burn for 3+ hours.

100% net wrapped hay here.