I used a razor to slice off the letters, then medium sandpaper in a sander, then fine, then wet sand with superfine emery cloth. The smoother the surface, the less the marker will bleed. Then, with an ultra-fine sharpie marker, I carefully hand-lettered 20 common problems found in hot tub service calls. I then re-assembled the unit using Mr. Sticky glue on the cap. (A common pool/spa repair adhesive) The dye was put back in using a turkey baster with an injector tip. An eye-dropper got the last of it in. With the cork back in place and the entire unit re-assembled with some glue, I’m ready to use this diagnostic tool ONLY when eights years of experience fails me on a tricky malfunction.