These traditional applicators for hot hide glue have several advantages over the familiar flux brush. The brush body can be trimmed to specific shapes (narrow, rounded, pointed) while the flux brush can only be trimmed to length. Better yet, as the fibers gradually wear out, hammering the bast separates the fibers and creates new bristles. Bast fibers retain their stiffness even when saturated with hot glue or stains, and they're rich in natural phytocides to prevent the growth of bacteria or mold in your glue. Bast is free of oils that might contaminate animal glues, and best of all, it can't rust!