There was a club in my area who was having an open house, and they advertised S&W Performance Center gunsmiths on site for free "cleaning and inspections" of any S&W handgun.
I brought along my 6" 617. During the summer, I shoot it every day down behind my house on the riverbank, and only clean it once a week. Basically, that's about once per 550 round Federal Bulk Pack.
They pulled the sideplate off (by prying on it with a screwdriver!), gutted it, and stoned all the contact points. I've stoned many S&W actions, including one 686, and as long as you maintain the same factory angles on all the parts, it's not hard to do. Remember, you are not trying to REMOVE material, just smooth it out. If you remove material, you will be damaging the action, possibly to the point of getting hammer push-off, since the parts won't be fitted properly anymore.
I asked him about using a plastic hammer to take the sideplate off. He said that, as long as you pry gently, you won't damage anything. He said he's never taken one off that way, and nobody else in the PC does, either.