I save grease from meats (hamburger, sausage, bacon, etc) and make a bisuit dough with it. (You know, cut the grease into self-rising flour, stir in enough milk to make a dough. Knead a minute and you're ready to roll) Roll it out as thinly as you can and cut to desired size with a pizza cutter. Place pieces on cookie sheet(s) and bake at around 400 till hard. Dogs don't even seem to mind if you forget they're in the oven and burn them a little. These don't even need to be refrigerated.