I've used pipe-cleaners (from tobacco shop) to clean sockets. There is the soft kind for delicate gently-smoked pipes, and a heavy-duty kind with stiff bristles for tarred-up pipes. Use the stiffy to break oxidation, and the soft kind to work solvent or deOx into the hole.
There used to be tube and socket cleaning gizmos. If you inherit some old-time tech's collection of stuff, there will be a few of these in there. I have not seen one in a long time.
For 1/4" patchbays, go to the gunshop and say you need to clean a .22 caliber pistol. The brushes come in nylon or brass: start with the nylon but I've had to use the brass on old mistreated jacks. You can also get a handy pistol-size handle just right for working in a live patchbay without taking all the plugs out. You can get all this in a kit, but then you pay for solvent and oil that may not be good for electronics; I found brushes and a handle in bags pretty cheap.