Things You'll Need
Acid dye powder
Large cooking pot
Change the color of a wool sweater quickly with a vat of acid dye. These vibrant dyes require no special mordants to impart their color to animal fibers. If your sweater is white or cream and its care label says that it is made of 100 percent wool, with no nylon or synthetics added, you can dye it at home on your stove top and expect it to reach a color true to that on the dye jar.
Wash your sweater by hand in a sink full of cold water. Add wool wash according to the instructions on the bottle. Allow the sweater to soak for 30 minutes, then squeeze out the suds and refill the sink with cold water. Pour in 1 cup of white vinegar and allow the sweater to soak for another 20 minutes.
Add 1/4 oz. of dye powder to 1 quart of hot water in a glass jar. Stir the mixture until the dye powder is completely dissolved.
Fill a large cooking pot with enough water to completely submerge the sweater (this usually means filling the pot 1/2 to 3/4 full). Bring the water to a boil and add the dye. Lower the heat to a simmer and stir the water until the dye is completely mixed in.
Add the sweater to the pot without rinsing out the vinegar water. Press it down into the dye bath, let it soak for one minute and turn it over. Do this several times to ensure even saturation of the fabric. Be careful not to agitate the sweater too much, as this can cause the wool to become felted and shrink.
Leave the sweater in the dye bath for half an hour, stirring occasionally. Pour the entire dye bath into a sink and allow the sweater to cool completely. Rinse the sweater in lukewarm water until the water runs clear, then soak it again in wool wash until all the excess dye has been washed out.
Double the amount of dye powder for dark colors or black. Achieving an even, saturated black often takes more than one dye bath.