Some pairs of dark wash blue jeans, no matter how many times you wash them, continue to bleed on other things. Unlike the typical fire engine red sock that spreads its dye only inside the wash cycle, denim stains occur simply when other things rub against them, even when they are completely dry.
Removing Denim Stains from Fabric
Blue jeans dyes, even when they are transferred between two dry garments, need to be treated as dye stains. There are a few methods of removing dye stains. One of the least labour intensive is to place the stained garment in the washer and instead of adding the usual detergent, add 1/4 cup borax and run the cycle. After the garment comes out of the washer, if you still notice a discolouration, mix up a 1:1:1 solution of water, ammonia and liquid dish soap. Wet the stain with this solution and scrub. Wash the garment again. It is important to check the garment after it comes out of the washer, before you put it into the dryer. Otherwise, you could set the stain.
Removing Denim Stains from Leather or Vinyl Items
Leather and vinyl can't just be thrown in the washer the same way that many cloth garments can be, so a different technique is necessary. Blue jeans stains in leather or vinyl should be thought of more as surface stains, like those you would find on your kitchen counters. Mix soap and a clear liquid dish soap together, then dip a cloth into your solution. Rub the dye stain until it is gone. Make sure to rinse the cloth every so often as dye transfers to it.