Ringo has growing crust around the mouth

[Shady]

It could be as simple as Feline Acne. There are mild cases which are most common, then (as pictured in the second link) it can progress into very severe.

I have one that from time to time gets a very mild outbreak. The stuff is black and kind of waxy, I just keep bathing the area with warm water, it's very difficult to remove and the sores if there are any are under that. If there is a sore I use a small amount of neosporin on a q-tip, to help it heal. It can sometimes take weeks though. You have to keep at it if that is indeed what it is.

http://www.valleypetnews.com/felineacne.htm

(more severe in this link)

http://www.fabcats.org/acneandstudtail.html

[kb2yjx]

I agree with the previous post about the acne. It is treatable, but get it looked at, it can progress to a really messy situation. Had one cat with it so bad, he could not eat.
I am glad the previous post has Persians. I have a Persian, Raven(COTD 12/9/04), she has a conditon called idiopathic dermatitis. Persians and Hyimilians(sp) are known to get this. It is also a brown debris that clings to the fur under the chin, around the mouth, and sometimes even in the space on the cheeks. Has anyone ever seen that. That was a possibility I thought of when I read about the affected cat in the first post. You never know with these creatures!!!!