I purchased the blue, green, black combo pack and started out hand washing them, as I was concerned about the color bleeding, and it did. After more than a year the black pair no longer bleeds, but the blue and green pairs both still tint the wash water, so I continue to hand wash them. I have purchased other brands that I machine wash on delicate cycle, as they do not bleed. So these get worn less often due to this issue, but I like them otherwise.