So I bought a Hoover carpet steamer today and went nuts in my car... I lifted up my rear floor mat for the first time ever (in 2.5 years of owning the car) to find some wierd stains under it. I know for sure nobody has ever spilt anything back there. I was using the Hoover cleaning solution that came with the machine, tried soaking it, scrubbing it and it got a bit better, but its still there. Here's a pic of it after cleaning it: Its not as dark as it looks... it just showed up like that in the picture (cheap camera) How do I clean this up?