I use WEN on Lola... We bought it off QVC for ourselves because it was all natural. Then Chaz Dean (who made wen) said he uses it every other thursdays on his labs... i decided to try it on my baby. It makes Lola's hair so shinny and soft... it works really well and it keeps her clean for about 2 weeks. The only WEN shampoo you cannot use on your dog is the tea tree. You can also use the oils he has the night before you give your lil' yorkie a bath.
http://www.chazdean.com/ChazDeanStudio.swf