I have two pair of PAL's. When I refurbished them I needed to remove the black foam bricks but they just turned to dust as I tried to remove them. I replaced with batting material from a fabric store. The material can be purchased in various thickness and I used the 4 inch thick material. It looks similar to fiberglass but is a synthetic material that is white. It worked very well for me and it is not "prickley" like fiberglass. The store was a fabric/sewing retailer call JoAnns. It is located in the quilting/batting area.