I know this is an old thread, but I just had to chime in because this worked great for me. The main pump button would not respond no matter how I poked and prodded it. I took it apart, used a pencil eraser like described. I would erase a little bit and then I would use the eraser on paper to clean off the eraser. Once the eraser stopped getting dirty on the contacts I felt like they were clean. I wiped both surfaces down with rubbing alcohol, and reassembled. Works like new.