Clothes that have recently been washed may smell sour due to a build up of soap scum inside the washing machine. Bacteria and mold grow in the dampness of the washing machine and feed on soap scum, which is typically made up of body oils, skin and soap residue.
To prevent the sour smell from freshly washed clothing, clean, sanitize, and deodorize the gaskets, dispensers and drum of the washing machine. Remove the soap, bleach and fabric softener dispensers, and wash them in the sink. Clean the rubber door seal, or gasket, with an old toothbrush or cotton swab and a solution of 1 cup of warm water and 1 tablespoon of bleach.
After surface grime on the inside surfaces has been wiped away, sanitize the washer by setting the wash cycle to hot and adding 4 cups of chlorine bleach to a top-loading washing machine and 2 cups of bleach to a front-loading washing machine. Pause the cycle halfway through, and let the bleach water soak in the basin for 30 minutes. The bleach water eliminates the bacteria and mold that has been growing in the unreachable crevices of the washing machine. Drain the bleach water, run a water-only rinse cycle to remove all leftover bleach, and use a water and vinegar solution to deodorize the washing machine and remove hard water stains. Add 4 cups of vinegar for a top-loading washer and 2 cups for a front-loading washer, and set the cycle to hot. Let the solution soak for 30 minutes, and rinse the machine with plain water.