I've done it.
I put a piece of batting 90 by 100 into the front loading washer and put the setting on handwash. Ran it through the cycle and put it in the dryer and dried it. It took a couple dry cycles to dry it. The end measurements are 75 by 96.
It turned out just fine. Had to go to work so couldn't take it out of the dryer when it was dry, so I'll have to put it back in with a damp towel for a few minutes to get whatever wrinkles out.
Aileen