According to Ugg's Boots Care instructions, never dry wet Uggs in direct sunlight or close to any kind of heating source. Authentic Uggs are resistant to the elements; small amounts of water will not damage them. However, if they become soaking wet, remove any outdoor dirt and debris, shake out the excess water and allow them to dry naturally in a shaded area away from the sun and the rain.
If Uggs develop spots on the surface caused by water droplets, these spots can usually be removed simply by folding the leather surface against itself so that the spotted leather touches clean leather. Then, gently rub the surfaces together, and the spot should lift. Because the sheepskin that Uggs are manufactured from is not waterproofed at the factory, Ugg highly recommends waterproofing the boots when they are new and have not yet been worn. Use a commercial stain and water repellent specifically made for leather. Waterproofing helps to protect the boots from dirt (which can stain wet uggs), water and oils, and it also extends the useful life of the boots. Waterproofing also helps prevent Uggs in darker colors from transferring dyes upon contact with clothing or other items. The boots are not recommended for wear in icy conditions, snow or heavy rain. Ugg's Boots Care instructions stress that the shoes should never be dry cleaned or laundered in a washing machine.