I just ran mine through running water a lot and shook it out. It seemed to work pretty good, but only if you do that often, after a while there was so much stuff on it i just went with tile.
I kept 2 pieces the correct size. I used just a little dishwasher detergent and handwashed it in the sink and then put it in my washing machine on the spin cycle to get the excess water out. I draped it over the tub to dry and alternated my 2 pieces so the geckos didn't have to wait. Now I use ceramic tile also.
When I first started keeping geckos I use carpet, and washed it in the washing machine. After awhile the carpet started to get fuzzies all over so I threw it ou and went with the good ol comics section. Now I have rack and just use paper towel