Have you seen the videos on "stripping" your laundry? If you haven't, it goes something like this: Fill your bathtub with water and then add some bicarbonate of soda, laundry detergent, and borax. Stir it up, add some of your clean clothes, and let them soak for a bit. When you take your clothes out, the water left in the tub is a gnarly colour that proves your washed clothes might actually not be all that clean.
Gross, but totally worth it.