How do you fix a non-working key on the Macbook pro 2016?
I found another way that seems to work and doesn't require a can of air: Hold the laptop sideways and while holding it like that, pound on the key. Pound as hard as you would if you were typing an angry message. Try to pound on each side of the key. Holding it sideways gives gravity a chance to pull the crumbs out. And if it doesn't work the first time, try holding it a different direction.

I've tried this method on several keys, including the large right SHIFT key. It seems to work pretty good. The SHIFT key still isn't fully back to normal, but is way better than it was.