It doesn’t matter if you are packing away your outdoor umbrella until next season or just want to freshen it up for what’s left of this one, here’s a way to keep it clean: tip the umbrella on its side and sweep off any debris. Whatever else is left will come off with a mixture of 1/2 teaspoon of dish soap and 1 1/2 cups of water that you can put in a spray bottle to mist the umbrella. Wipe off with a wet sponge and air dry. If you have stains like bird poop, apply a mixture of equal parts of white vinegar and dish soap. This honey-like consistency will soak in then you can wipe away with a wet sponge.