i bought some sheep skin slippers from a thrift store but they do not have washing instruction and i am guy so i do not know (not saying that all guys are washing stupid but i am)
Turn them inside out and hand wash the wool part using a mild liquid hand soap, not a detergent. Here is a good link that explains the process.

Turn them inside out and hand wash the wool part using a mild liquid hand soap, not a detergent. Here is a good link that explains the process.
References :
http://www.aussieslippers.com/pages/how_to_wash.html