Do not use a drier and keep away your sheepskin boots from direct sunlight.
Do not scrub too hard your boots, use soft brush to remove a dry dirt.
Waterproof your shoes again once it is totally dry.
Use a mixture of soda (2 teaspoon) and corn flour (2 teaspoon) to soften and deodorize the inside of your sheepskin footwear. Shake your shoes with the mixture and let it stand overnight. Shake the excess out the next day.
Cleaning will remove some of the natural oils, so remember that your footwear may not look the same afterwards.
Be careful with dark color dyes, they may run after cleaning.