I did try contact cleaner before I changed out the keyboard. It had a minor improvement. A few keys worked that weren't working before. And I cleaned the cable connections a couple of times when I replaced the keyboard. Unfortunately, these eight keys remain bad.
At my desk, I have a dock and a USB keyboard and mouse. I just find it a pain to drag the keyboard around for meetings. I may have a small keyboard that will work in a pinch, but I would still like to fix this if I can.