[Christien]

Sounds crazy but:

Hit it with carpet cleaner - lots. Let it soak in for a few minutes, then scrub the living crap out of it. Then (here's the crazy part) hit it with a power washer. Yes, while it's still in the car. Then wet vac it up, really well and thoroughly - press the vacuum nozzle down with some force to squeeze as much out of the carpet as possible. Leave the doors wide open for a day or 2 to let it dry out. Make sure you let it dry in a very dry climate, so all the water can evaporate. Use a dehumidifier if necessary.

You'd be surprised how little it sprays. Yes, it will get some degree of spray all over the dash and windshield, but it's nothing that's going to damage vinyl or plastic - it'll just wipe right off.

This is how detail shops and rental car companies detail their cars.