You force the inner chamber to twist in the direction it would eventually go to unlock. Most locks inner core will have a tiny bit of play. You then go down the line pushing each pin up until the split gets stuck in the top, outer part. Once all pins are "out" the inner barrel will turn, lock picked.

This.
You'll get it "smooth" and the first winter it's a bit icy and little ones slip on it you'll regret messing with it.
A lot of the "not smooth"-ness IS probably gnarly old moss/lichen build up that the power washer will do a decent number on.