As time passes, silk flowers may get dirty and need a bathtub. If your flowers are older or you spilled something about them, then they can develop yellowish stains. Florists and craft shops sell spray-on silk flower cleaner for tough stains, but you might be able to remove the yellowing using cleansers you already own. Before investing in a can of cleaning spray, give old-fashioned water and soap a go.
Take the silk blooms out and blow them with a can of compressed air or a blow dryer on the no-heat setting. Remove as much dust as possible.
Put 2 cups of salt or dry white rice in a plastic zipper bag. Place the silk blooms in the bag facing down. Zip the bag or hold the top closed across the stems. Shake the bag for 30 seconds. If you use salt, then shake the blooms over the sink or outside after shaking them in the bag to remove stray grains.
Mix 1/2 cup of white vinegar and 1/2 cup of water in a spray bottle. Mist the flowers with the solution and allow it to sit for 15 minutes.
Fill a sink with lukewarm water and add 2 teaspoons clear, unscented dishwashing liquid.
Swish the flowers in the soapy water till the stains are gone. Rinse the blooms with cool water and dry them on several layers of white paper towels.
Boil a pot of water if your blooms are wrinkled or flat after drying. Hold the flowers in the steam, above the surface of the water, for a few seconds to whisk them up.