Does your cricut mat look like mine? I'm sure yours looks better than mine does.. mine is HORRIBLE! But, I brought it back to life with ScraPerfect's "Best Glue Ever". I haven't used the glue for anything else but to make my cricut mat sticky again, but I'm sure with that name, it works on other things too!! You're supposed to clean off your mat before you use it, but I don't. Gotta be a rebel sometime =]
I use an old gift card and spread the glue around on the mat. You let it dry for a couple of hours and it will be even more sticky than when you buy them.