Black residue from footpockets

I don't know what exactly causes it, but it's a manufacturing defect having to do with the material used. Some H Dessault footpockets would shed black powder just sitting on the shelf. I complained to the H Dessault distributor many times, and had many replaced, only to do the same at a later time I suspect. When the new H Dessault footpockets came out (about 2 years ago) it looked to me like the problem may have been resolved, but it became a moot point since they're now no good/too soft anyways. If your H Dessault footpockets are doing this, it will continue until the f/p have the texture of an old tire, then it will stop.