Big sheets
of tissue paper (like the ones you get when you buy a shirt), a
piece of luggage flattened out, a seat cushion, a coat that's been in the closet
for six months, even two cardboard scratching pad replacement boards fastened together.
If you are not sure, check by placing a mirror in front
of your Schnauzer's nose and look
for condensation or place a
piece of tissue paper in front
of your Schnauzer's nose and watch
for any movement.