Mr Bump my Kailh Big Switch had a very noisy spring, so a couple of days ago I opened it up.
This was a bit of a challenge because my switch opener is 4x too small, and the clips on the Big Switch are very stiff. Eventually managed to separate the top and bottom with some care and brute force.
I applied a generous coating of lube to the shaft and sides of the stem and the matching surfaces of the housing, and the outside of the shaft in the bottom housing. I didn’t lube the spring directly because it picked up enough from the shaft.
Curiously, the only sign of factory lube was on the contact leaf and around the tactile bump on the slider.
Anyway, Mr Bump complains a lot less now, and is much nicer to press.