Whatsthe best way to clean the cloth and keep it clean. When I had it installed the person told me to take a dustbuster to it once a month and to keep it brushed. I do that but after about 3 months it feels dirty and it doesnt seem like the dustbuster trick is working. Can anybody suggest something to clean the cloth with? I was thinking about the cleaner in the can but I diddn't know if that was a waste of money. Thanks in advance