HP 21 not powering on - repair/troubleshooting advice

[dmh]

(02-03-2021 03:19 AM)[kby] Wrote:  If there are holes in the back of the keyboard assembly, squirting in a tiny amount of sexigecimal g5 and working the key sometimes helps. Unfortunately, I seem to recall most Woodstock’s don’t have any holes.-kby

There are holes at the back of each key.

What is the product you mentioned as google came up with nothing?