Some folks wonder if it really is necessary to separate dark clothing from light when washing them. I would still answer “yes” to that question, unless you want to have grey underwear and socks.
There is a product available in the grocery store that will help if you accidentally put that fushia towel you picked up for $10 in Florida last year in the washing machine with your brand new white shirt. The product is called “Color Catchers.” I have not used it but I have friends who swear by it.
Be sure to follow the label directions as you use it in the washer and do not dry your bleeding-red towel with your light clothes after you try the product. The idea here is that you have to re-wash the clothes but the dye that deluged your light clothes should come out.
Think of this as the “morning after pill” for washing machines.