As for my Olfa mat, I tried this. I put it on hte back pirch, wet down a towel,covered with other part of towel. Wet down with vinegar water... I used my mushroom brush, not so good. Scrubbed with teh wet towel...Some better. I have VERY deep cuts in my mat... I keep having trouble with blades, seems like they don't stay sharp for very long and I tend to lean very heavily on them to get them to cut. I only use one or two layers of frabric, so I don't know what I did wrong.... I will let the mat dry and maybe try it again tomorrow....And lesson learned, I will take better care of hte next one which hopefully will be bigger!
Ellhe