Ever washed your polyester filled pillows and get them out of the washer all mushed up in an odd shape? Well, do a little pre-wash work.
Take a darning needle and thread it with heavy yarn. Then run the yarn through both the cover and the filling and tie the same way you would tie a quilt.
Do this in different areas of your pillow and then toss in the wash. When it is done it should be in the same shape as when you threw it in. I never dry my pillows in the dryer but do hang them to dry on the clothesline.