Get a large cleaning bucket. Fill the bucket with 1 gallon of clean water. Pour in 1/4 cup of table salt. Then add 1 cup of vinegar. Stir the water to make sure the mixture is evenly distributed.
Place the garment in the water. Make sure that it is fully saturated. Let the garment soak in the mixture for 24 hours.
Once the garment has soaked for 24 hours, remove it, and clean out the bucket. Fill the bucket with clean water, and place the garment in it. If color bleeds out from the fabric, repeat the vinegar mixture. If the color does not bleed, let the garment dry. The color has now been locked into the garment.
Washing with cold water is better for most clothes. Turn clothes inside out before washing them to prolong the color. Continue to sort clothes by color. Line-dry the clothes when possible, since heat can remove color from clothes. Keep the clothes out of the sun as well.