Go on line to the maker of the mat. they will have instructions. I soaked an old mat for several days and it really helped. I had to weigh it down in a shower stall, and kept it under water. then used a scrubber. Nylon works well...tooth brush, etc. Each company will give you instructions. I found a brand new mat at a Thrift store that was gray, without mentioning the name, and it is really hard on blades. I don't use it anymore. The materials that were used for making the mat were not as good as others.
June in Cincinnati