Oh, the joys of being a landlord. You get to wake up in the middle of the night all excited that you just thought of a cool easy way to clean those nasty stains the last tenants left in your carpets.
So, here's my trick:
1. Don't waste money on that scrub brush they sell next to the various carpet powder cleaners.
2. Spread the cleaner powder over the affected areas ... the whole room in my case!!!
3. Remove the suction hose from the vacuum and put the vacuum on its lowest height setting.
4. Run the vacuum over the area so the rotating bristles of the vacuum can work the cleaner powder in.
5. ... lol, duh, put the hose back in and vacuum.