As an old time watch and clock repairer (not maker), I've always believed that disassembly and cleaning works wonders. Old grease solidifies, oil dries out and becomes sticky and just squirting something into an assembly is a crap-shoot, you can't tell where it all goes, or not goes. (but it is worth a try, just be aware that a disassembly might be a day or two away after all). Unless something is worn out, a good cleaning and proper greasing (not too much) ad you'll have a new switch.