Am fairly new to the forum and have noticed several threads on color transfer. I am not aware of how to remove color already on the bag if it's untreated, but I have a trick that helps prevent it. Wash the jeans at least 3 times using warm water and a cup of white vinegar. Dry in a HOT dryer for at least 10 minutes. Denim is usually dyed with indigo, which saturates the cotton and gives the lovely dark wash, however most makers don't wash the excess from the material before you get it. You do not need to completely dry the jeans in the dryer if you are afraid of shrinkage but it helps.