1) switch the words "apparently" with "temporary and probably worse off", there's oil in there!, which mixes with dust to form bleh, most mechanical switches claim self cleaning

Self cleaning is debatable, A co worker pulled some beige box 386 out of the ditch a few years ago and I nabbed its keyboard once he found out what it was, thumping on the non responsive keys fairly hard for long lengths of time yielded a good clicky keyboard. Worked mostly great daily for over a year, then I got my IBM and the ditch keyboard went into the room on a computer that is not used that much, in the end it had reverted back to its original state in a couple months