Mix together one cup of white vinegar and 1 tbsp. of baking soda in a bowl. Apply the mixture to a washcloth and carefully rub it into any stains on the garment. For stains in heavily beaded areas, use a soft-bristled toothbrush to rub it into the fabric around beading. Let sit for 30 minutes prior to washing.
Fill your sink with three quarts of cold water and ¼ a cup of gentle laundry soap. Mix the two by stirring the water thoroughly with your hands for one minute. Submerge your garment into the solution and make sure to soak the fibers well, gently swirling it around for five minutes. Leave in solution for another 20 minutes.
Drain your sink and rinse it out with water, then hold the garment under running cold water for five minutes to rinse out the soapy solution. Set your garment atop a towel and cover it with another towel, then press down over the towel to soak up water. Place your garment in a cool, dry place, smooth it out and allow it to air-dry.