WHEW!
I remedied my first RIR pasty butt a couple of days ago (thank you, YouTube) and from reading these comments, I must have done it correctly! I have another RIR chick that has a pretty big gob hanging, but wanted to monitor the first one after my treatment before I repeated the process on another.
I did the warm water basin dip, submerging their butts for about 10 seconds at a time and gently removing it with my vaseline-covered finger, followed by a warm blow-dry. The chick didn't seem to wig out too bad, and her bum definitely looks better!
I'm doing the other chick today.
Strange that only the RIR's seem to be presenting with this unpleasant condition. The 2 barred rocks and 2 orpingtons have nice, clean booties. :-D