I had issue with my XL's pad. The pad had become sticky, and it was slightly shaven, presumably due to the excessive hard hitting pads from previous users. I cleaned with alcohol and such, but the stickiness didn't go away, and I noticed that there was a bit too much gap between pads and touch sensor.
I found out about using electrical tape on pad on YouTube, and it works very well; no more too much gaps, and the tape covers gummy sticky pads.
The tape must be applied to the back of the pad, not the touch sensor!
I think electrical tape method is much better than the cork MPC Stuff sells. I think the cork would've been way too thick for my situation.
One little downside is that you have to apply tape a few time a year (if you use pad a lot), since the applied tape moves little by little each time pad is hit.
P.S.
I found the YouTube video (it is MPD32, but I used the exactly the same trick):
http://www.youtube.com/watch?v=_mI4SutQJpQ