I was looking in the wrong place -- found it. This was posted by BellaBoo. She wrote:
I was reading quilt blogs this morning and kept clicking random links and found this info about mats.
If you have a self healing cutting mat it needs to be re hydrated to stay self healing. When the moisture is gone the mat dries out and will have cut marks and dull your blade. Soak the mat in room temp water for about and hour, let dry. That's all you have to. The mat will be soft and be like new again. I have one old mat soaking now. I'll post if it makes a difference. I don't think June Taylor mats are self healing. I have an Olfa one soaking.
The part I wrote about the brush came from another posting I had read.