I agree with just letting it soak, then spinning out the water. I would use regular dryer heat, as it is the dryer heat that will ultimately shrink the damp batting. Assuming your Warm and Natural is needlepunched through scrim (I'm not sure that it all is, but I think all of their cotton batting is), it is tough enough to hold up to the dryer. Just be sure you use a dryer big enough for the batting. If you have to pack the batting in the dryer you can end up with burns in the batting because it doesn't have enough space to tumble. If your dryer is too small, I would load the soaked and spun-out batting into a laundry basket and take it to a commercial laundry and use one of their large dryers.