When I was about 12 yrs old, I watched me dad clean 3 squirrels in about 20 seconds.
I was rather nonplussed.
He had a great method (which I'll have to ask him about it as a reminder) that I'm still fuzzy on.
I think he started by cutting off the arms, then made two cuts (I think) alongside the belly.. followed by the cut underneath the tail. Hold onto the legs, step down on the tail and then pull straight up. Can't remember how he got the patch off the belly.. then he'd make a vertical slice down the chest/belly and run his finger through the cavity to expunge the innards. Finally, cut off the legs at that joint and cut off the head, done!
I know I don't have it quite right as he seemed to move so fast, but it was quite interesting to watch.
BTW, they were fresh kills, too...