I have an olfa, self healing. I looked at the olfa site as well as information from this group. Self healing mats love water. Some have soaked theirs in tubs. I have a large Olfa, and I did not think my tub was large enough. I lay out a towel on my dining room table. A soft brush, such as vegetable brush. I use the kind that is used for washing dishes, that, the top can have some dish detergent put in it.
Anyway, I put a squirt of dish detergent in a bowl with distilled water, scrub my board down. Then go over it with clear distilled water. Let it dry, then use a cutting board smoother. Board is as good as new