Dry the newly dyed fabric over a drying rack.
Place the fabric in a bucket and cover with undiluted white vinegar. Allow the dyed fabric to soak in the vinegar for 15 minutes to help preserve the fabric dye color.
Remove the fabric from the vinegar soak and wring it out. Wash the fabric in the washing machine with laundry detergent. Add 1 cup white vinegar to the rinse cycle to further set the colorfastness of the fabric.
Hang dry the fabric on a drying rack to prevent fading that occurs in the dryer. Dry the fabric out of direct sunlight to avoid natural bleaching and fading.