Slip Out the Insoles
Most UGG boots have insoles that are removable. The insoles have a sheepskin layer on the top of the insole and a flexible, plastic bottom. To remove the insole, you can insert the non ballpoint portion of a pen into the boot. Use the pen to wedge between the boot's lining and the bottom portion of insole, which should help you lift the insole out of UGG boots on sale. Use the same process to remove your other insole.
Hand Wash
Resist the urge to toss your insoles in the washing machine. Washing them by hand can extend the life of your insoles. To begin, prepare a bowl or basin of warm water with a mild soap -- a shampoo or body wash will work. UGG also sells a sheepskin shampoo designed for washing your insoles and boots. Add your insoles to the basin and swirl them in the soapy water to ensure they're fully saturated. Allow the insoles to sit for five to 10 minutes before removing from the water. You can either rinse the insoles clean with warm water or empty the soapy basin, replace with warm water and rinse in the basin itself.
Drying
If you slip your insoles back in your UGGS on sale when they aren't fully dry, you could have a smelly, squishy mess on your hands. To keep this from happening, shake out as much water from your insoles as you can after rinsing them, then dry upside down over a towel that can absorb moisture. Place them out of the way of direct sunlight or heat -- the heat can cause the wool fibers to shrink up and mat. Once your insoles have had plenty of time to dry, you can slip them back into your UGG boots.