Has anyone used this stuff, and is it any good? I've seen the ad where the stuff foams up, then you vac it up.

I would have thought that the wet foam is not a good thing to be sucking up with a vacuum cleaner though. Or is there something I'm not getting with the ad?

Anyway, just wondering, as I have two large carpet mats (maybe 3x4m each) and they need a good clean, and its either preen or hiring a carpet cleaning machine for a couple of hours. A couple of cans of preen is definitely where I'm leaning to, as they are so much easier to throw into a trolley as opposed to trying to lug the cleaning machine with two little ones.