I have some black spots of mold on my floor joists in my crawl space. The floor joists are insulated with fiberglass, and there is some mold on the fiberglass also. This makes it hard to wipe-off the mold. How can I get rid of the mold - what chemicals do I use? Note - I have added a 6 mil vapor barrier, installed a dehumidifier and closed the crawl space vents. This has helped and no new mold is growing. I still need to get rid of the "old mold".