The proper amount of oil to put on a blade is applied thusly:
Use white, unscented, not made from recycled fibers tissue paper or toilet paper, folded into a rectangle that will fold around the blade. Put just 3 or 4 drops of oil on the paper. Starting an inch above the nakago, with the paper wrapped around the back of the blade, wipe up towards the point and then go back to the same spot and wipe that last inch down towards the nakago. This ensures that you won't drag a rust particle from the nakago over the polished blade surface.
Next, use a clean pad of the same paper to wipe off the oil you just applied, using the same technique. The tiny amount of oil that remains after wiping is all that is necessary to protect the blade. If you use too much it will bead on the blade and eventually will foul the inside of the scabbard.
Grey