The keyboard quit working properly and characters would type spontaneously even when I connected an external keyboard. I wanted to go in and see if I could clean it up.
Once I got in there it wasn't clear that any cleaning would help. Fortunately, I had a second MacBook Pro on hand for parts since it had suffered the black screen issue and wasn't worth the expense to repair. I removed the keyboard from that one and put it into this one. Wihout iFixit I wouldn't have had a clue about how to do any of this! Being told what tools I'd need for the job was immensely helpful! The result: success!
I labeled ziploc bags and put different sets of screws in them as I went along, numbered etc. so that when it was time to reassemble I wouldn't be baffled by which screws went where. As for swapping out one keyboard for the other, it didn't dawn on me until I was already removing keyboard screws that I didn't have to, that all I had to do was remove the entire facing that contained the keyboard and trackpad and swap it with the other one. That just pertains to the fact that I had that available to me.