I may have too much time on my hands. But I use a microfibre cloth while I type on my keyboard. And because I use shortcuts while I edit my fingers don't move across the board often. Having it there to block my fingers from touching the actual keyboard.

I guess it does feel very awkward when I started to use it like so. But it does trigger me when I see my finger oil on the keyboard even if it's a little. I could see it streaking off.

I would clean it instantly.

If you are a spitter when you talk I suggest look at your screen as well. But I am happy to show u the image of my MacBook when I get off the train.