6. Clean and store umbrellas. Cleaning umbrellas can be a bit tricky. If there's just a bit of dirt and pollen on it, simply dust it off and store it inside until summer. If it needs a bit of a scrub, wash it off with dish soap and a sponge. If you have a vinyl umbrella, a detergent made for convertible car tops can do the trick. After you're done washing the umbrella, make sure to let it dry completely in the sun for a couple days. Never store an umbrella that's remotely wet if you want to avoid mildew!