I recently purchased two butterscotch handled brushes for restoration/reknotting: one a Fuller, and the second a Rubberset 153. Both brushes have a butterscotch Bakelite lower handle and a hard, black rubber upper. My question is thus: does anyone have any experience/knowledge as to whether the butterscotch color on each handle is through and through or merely skin deep? If skin deep, then how does one clean up and highly polish the handle without eliminating the butterscotch color? I noted on one thread where a Rubberset butterscotch handle had turned an entirely different color when polished. Luckily, the new color was very attractive. Thanks in advance for the help.