Whether you went swimming in your watch or just dunked it into the sink while doing dishes, you may notice drops of water collected between the face and the crystal. Use the power of nature, courtesy of evaporation, to solve the problem. Heat energy can break the binds between water molecules, causing the liquid to turn into a gas. If the methods for evaporation don't work, you can use a few common household items to draw the water out without opening the watch.
Set the watch in direct sunlight for two to three hours. The sun's rays, focused by the crystal, may be able to evaporate the collected water.
Use a hair dryer on its lowest setting to heat the watch. The rise in the surface temperature of the watch may cause the water inside to evaporate.
Hold the watch face next to a lit, hot light bulb. Depending on how hot the metal of your watch gets, you may want to handle it with gloves or a towel.
Pour a handful of uncooked rice grains into a resealable plastic bag. Seal your watch inside the bag and keep an eye on the moisture level. The rice should draw out and absorb the moisture. If it doesn't, try placing the sealed bag in direct sunlight for one to two hours.
Press any buttons on the side of your watch and tilt the watch so the depressed buttons face the floor. If water got into your watch when the buttons were pressed, you can try to drain the water out the same way.
Dried-out rubber gaskets on water-resistant watches can allow moisture to seep inside. Have your gasket replaced if the watch is more than two years old.
Avoid exposing your watch to sudden, extreme temperature changes. The air trapped between the watch crystal and the watch face can condensate if it's heated then cooled rapidly. Prying off any part of your watch (the back or the crystal) may void your warranty. Use only non-invasive techniques if you want the warranty to remain valid.