Do you have dirty mats? I did. At one time, they were beige and then I spilled coffee (a lot of coffee) on them, so I tried something desperate and it worked out great. I put the mats, all 4 of them, in my washing machine with Oxiclean. Well, they came out great, totally clean, soft, and like new, not a spot left on them.

If you try this, make sure you postion the large mats against the sides of the washing machine, rubber facing the sides, and the smaller mats in front of those. The idea is to balance the load so the washing machine doesn't go beserk. I also put them in the dryer and that worked out great too.