This is an old tip valuable to everyone. Whether it is new or prewashed fabric or clothing, this dye fast recipe works great for pennies. I'm sure the measurements may vary from one source to another, but this works great. 1 cup Vinegar, 1cup Salt, mild or baby laundry soap to a full wash load tub of water. Recipe designed for up to 10 yards of fabric. May need to retreat if the fabric has a serious bleed. Have used this on everything from quilting fabric to dental scrub uniforms. Noticed that as timepassed my scrubs stayed brihter then those of my coworkers.