I’ve got a classic wooden rolling, swiveling desk chair. It has begun to loosen at the joints. The screws that need tightening are set in holes that are covered by round-top wooden plugs that, I assume, are held in place by pressure and maybe glue. The whole chair is covered in a glossy, reddish stain-varnish; the underlying wood (oak, I think) is lighter in color than the finish, so any damage to the finish would be visible.
How do I get those plugs off – and then back on – with the least amount of damage to the plugs themselves, and the finish that covers them and the surrounding wood?
No can do, I think. The plugs are a goner. The way to get them off is to drive a drywall screw into them. When it hits the screw underneath, it’ll begin to spin the plug out of the hole. You can buy new oak plugs at Home Depot and places like that. You’ll have to restain them, though you can do that with more or less anything – even a magic marker.
If the plugs are glued you are likely SOL with respect to damaging them.
If they’re not glued, but in too tight for gentle prying to pop out, you could drill an 1/8" hole in the center of each, and thread in a wood screw to push against the base and extract each plug. After tightening, remove the plug screw and fill the hole with color matched wood putty, or wax.
Use a utility knife to cut the glossy finish around the plug, so that it doesn’t tear when you take it out. I’m assuming here that the finish flows over the plug.
Gentle pry out is the game plan. Opposed tools (chisels or utility knives), each applying gentle pressure should pop the plugs out without damaging them.