When you purchase jeans in a dark wash, the dye sometimes bleeds. This can be a problem, leaving you with faded jeans and staining other clothes in the wash. Some people recommend adding salt to your wash to minimize this problem, but it does not always work.
Salt and Dye Bleeding
The purpose of adding salt to the wash with brightly colored or dark clothing is to make the dye less soluble. This may help keep the dye from bleeding a lot. However, salt is only potentially useful when washing clothing made from natural fabrics, such as denim and cotton, and has no effect when washing synthetic materials, such as Lycra or polyester. Most jeans are made of either natural fabrics or a combination of natural and synthetic materials.
How to Use Salt in Wash
While the water is filling the washing machine, you can add 1 tablespoon of salt to the machine for each brightly colored item in the wash load. Do this each time you wash the jeans, because salt doesn't permanently affect the colorfastness of dyes in jeans.
Other Steps to Minimize Bleeding
Adding vinegar to your wash may also help make your jeans less likely to bleed, as can washing them inside out in cold water on the gentle cycle with a mild detergent. Washing your jeans by hand is even better for preserving the color of your jeans and keeping them from fading.
Many more expensive brands of jeans recommend you limit the number of times you wash them to help them keep their color and shape. This means not washing your jeans every time you wear them. Spot treat any stains, or hang the jeans near the shower to steam clean between washes to minimize stains and odors.