stackmat g5

My mat has a dirty spot and I'm curious if anyone knows the best way of cleaning it.

Hi Everyone, I curently have a gen 4 stackmat with a mat. Should I get the Gen5 stackmat? Thanks!

So I've had a stack at G5 for about a year, and I replaced its batteries only once about a month ago. Today I decided to use it (on two pad mode) and when I stopped the timer it displayed 888:888 and when I hit the power on button the timer went to four pad mode, which is its default mode. I...