Take it apart and take the poly out. It'll melt. If you use a lot of steam or starch I would add a layer of foil or the board will warp before long. I would use one layer of Warm and Natural batting and a cotton canvas or cotton duck cover. In a class I took with a national quilt teacher she told us the teflon covers allow too much slipping when you press and let your pieces distort too much. You want a cover with some grip.