What's that funky smell?

Our apartment smelled terrible. Often times it's because of diapers and the fact that my roommate keeps the thermostat up so high... So, when she left for the weekend I went through and took all the trash out, and cleaned up and down. But when I came home from work the smell was still there! I got out the disinfecting spray and cleaned a little more. But then it hit me. When I set the bottle down on the dryer I got a good strong whiff of the funk...it was coming from the washing machine. She had a load of laundry in there from who knows when that had begun to grow stuff. Ha! Mystery solved.