I don't know if this will help but the following information came from an Olfa dealer (www.ollfadeals.com). I have never tried it but always intended to.... In order to clean and condition your Olfa rotary mat, you can actually give it a bath.
Put your mat in the bathtub and use 1/4 cup white vinegar to a gallon of tepid (not hot) water, and a couple of drops (squirt!, squirt!) of mild dishwashing soap. Using a mushroom brush or other mild bristle brush, create a lather and gently clean and condition your mat. Rinse the mat and let air dry or dry with a Turkish towel. The mats love moisture. It helps keep them supple.