Cranks and quacks tells uss that after pyramids, magnets is just the thing to keep razor blades sharp… or as John S Forbes states in his 1930 patent on a magnetic razor-conditioning device:

…a simple and effective means of producing or maintaining a good edge on a razor blade by magnetic influence.

While the patent description is somewhat tortured and hard to follow, it seems like the basic idea was that storing your razor on a magnet should keep the blade sharp. Needless to say, reality don’t work like that.