UGG boots have a sheepskin exterior. As anyone who has ever owned a sheepskin or suede product can tell you, it is both a durable and delicate product. You can apply a stain repellent spray to your shoes before wearing them -- and UGG makes one specifically for its products -- but even that will not guard your footwear against all stains. It can be tempting to scrub away at blemishes with soap and water, but many soaps can themselves stain sheepskin. Removing a soap stain is not always easy, but can be done with the right products.
Wet the stained boot by running it under light, running water. Do not saturate the boot to the point that you can feel moisture from inside the boot. The goal is to get the stain wet, but not to soak it or drench it in water. Wet the soiled portion of the surface thoroughly but conservatively.
Make an even mixture of water, sheepskin cleaner, and sheepskin conditioner. UGG makes both of these products, but you can use non-UGG brand products, if you prefer. You must dilute these products in water, following the manufacturers' instructions. UGG emphatically warns against applying the chemicals directly to the boot.
Soak part of a washcloth or sponge in the mixture.
Apply it to the stain, being careful to keep your application to the moistened area of the boot. Do not apply the solution to dry suede.
Rub gently, just enough to get the solution to penetrate the stain. . Do not rub too hard or vigorously, as doing so may damage the quality of sheepskin.
Rinse the treated area with cool water, using the same gentle rinsing technique you used to wet the stain initially.
Fill the boot with newspaper to help it keep its shape while it dries. Allow it to air dry, away from direct sunlight or heat, for at least 24 hours. Do not heat the boot in an attempt to dry it faster.
Spray the boot with a sheepskin stain repellent once the stain has been removed or reduced to your satisfaction. Again, allow the boot to dry 24 hours before you wear it.