you can get a roll of metal screening from home depot/lowe's for a couple bucks. i forget how many covers i was able to get out of a roll but it was well over 100. i cut them big, probably the size of the whole trap, then bend over the pan and then down around the coils so its not just a pan cover but a coil cover as well so both are free from dirt and have no problems firing. they usually get tore up easily from a catch, but i have a stack of them in my trap pack, so no worries. its certainly the quickest and cheapest way i've found so far. those custom slip-on covers are nice, but i can see them getting lost easy. when my screen covers are a nickel a piece and take all of 5 seconds to cut, they're the most efficient way i've found.