have you tried wiping it down with a baby wipe and letting it dry thoroughly? I got my Cricut on April 1 and I just stopped using my original mat. I'm going to try the spray adhesive idea though
the baby wipes clean up all the scraps and junk that gets stuck to the mat. I think my origional mat was defective - half the sticky got stuck to the plastic when I took it off, but I was able to get it to last quite a long time