I'm working on stuff that doesn't require cutting today so good opportunity to clean my 4 year old matt. I've done quick heals - (wash, rub, scrape) but never a "deep" healing.
I laid the mat out, wet several dish towels and laid them on top. I'll leave it like that for about an hour or so.
Will let you all know how it comes out. Darn ... wish I had taken a before picture.