I actually did a little experimenting the other night with a mat out of another car... it just had some spots and the mat just had that look of having an overall layer of dirt film on top. I did a little spot treatment and blotted up the stains as much as I could and then took a steam cleaner that my mother had bought (sort of like a steam buggy but a bit better) and went over it with one of the attachments that had a micro fiber bonnet on it. It seemed to get quite a bit of the top stuff off. Then I saw this earlier... http://properautocare.com/hotwaex.html and man I bet it does an AWESOME job lol.