The phenomenon of recording tape oxide (see WFTD archive Oxide) coming unglued from the backing (the tape). This manifests itself as tiny brown flakes that are deposited around your tape transport components. All recording tape sheds. It is caused by several factors, including the quality of the tape, age of the tape, the conditions in which the tape has been stored, how much the tape is handled (how often it is played), how smoothly the tape transport handles the tape, and the abrasiveness of the various tape transport components. For example: if your tape machine is out of mechanical alignment such that the tape scrapes against the reels, you are going to have more shedding as the bond between the tape baking and the oxide is weakened prior to passing through the other transport components.