If you've stained your white clothes by washing with colored clothes you can undo the damage by soaking them in warm water with baking soda, salt, and detergent. Be generous in the amounts but you wont need a whole box of salt I would use no more than a cup and at that it would half to be an extreme case for that much salt. If your issue is colored clothing that has bled onto other colors rewash immediately skip the warm water and go directly for cool to cold add your salt and detergent but instead of baking soda use a generous pouring of hydrogen peroxide, allow your clothes to soak for about 30 min and rerun the wash cycle. Be sure to check every garment before you dry it as the stain can become permanent after it is dried so keep rewashing until you no longer see the stain. If you have already dried the articles than you may try this, but your best results come from the wash cycle that the stain originated from. Also for future reference you might try this little trick for any new garments that you get to keep their color from running in the wash; Add 1/2 cup of salt to the wash cycle along with your usual detergent.