Small problem, dude... they aren't worth eating after you gas them. The meat will taste like exhaust. I guess I understand the no shooting predicament you found yourself in, but there are other solutions. Get a fucking bow and some tri-tip arrows, or if you suck at that, a cross bow and some hunting bolts. Silent, deadly, and they don't tear the shit out of the meat. Just make sure when you clean them that you don't cut through their bladder because they have some fucking rank piss and that will taint the meat if I remember correctly. We didn't have possum in New Mexico, but my cousins had hundreds of them (and nutria) down in Breaux Bridge. Soak the bastards in salt water overnight just like you would a rabbit or squirrel and they firm up and all the gameyness leaches out of them. Very versatile animal, great just roasted with some cayenne and stuffed with oyster dressing, chopped up in stew, or pulled and fixed up in an enchilada just like, again, rabbit or squirrel. A hell of a lot easier to prepare than nutria or chinch which both have a swamp grass taste and have to have their soaking water changed a few times to clean the taste up.