Use your poly batting for any bloomin' thing you want. It doesn't have to be just for dog bed or practice items. I have learned to close my ears to people who won't use anything but fabric they bought at an LQS for $13 a yard even though the same fabric--exactly the same manufacturer, finishing process, etc--can be had at Wal Mart for $7.49 a yard. These are the same people who refuse to use Coats and Clark thread. They also won't use a poly cotton blend even when it is just the right color for their project. Use and enjoy what you've got. froggyintexas