Here are the directions I used. Use a mild detergent and the mushroom brush to clean. Separate step from the moisturizing. I have a farm kitchen sink so all but my big mat fit in there. The big mat I did in the bathtub. It was too wide so I soaked it one way and then other. Dry flat.

OLFA Cutting Mats love moisture!It is recommended that you soak your mat from time to time. Your self healing mat loves moisture.

To soak it, put your mat in a bathtub or large container (would have to be large so it can lay flat) and soak it for 15-20 minutes in a solution of 1/4 cup white vinegar to every gallon of cool water. Let me repeat, cool water. Do this every so often to help extend its useful life.