"Son some keys on my keyboard on my Timex 1500 does not work!"
"Dont worry I'll check it out."
After opening case, "Maybe the contacts are dirty? Ill get the rubbing alcohol and clean them!" (Even though the unit is not even a year old and there is no fan.)
Son grabs a cotton swab and dips into bottle, pulls out contacts and starts scrubbing.
"Oh no the contacts are disappearing.", the son says grimly and under his breath. A dark shadow passes over his soul.
"It does not work any more mother."
Son puts computer (doesn't have a real keyboard) together and it gets put into a box in the closet for the next 30 years.
...
SMR produces a replacement keyboard and son renews involvement in 8-bit computing of the Sinclair variety.
"Mom do you have that Timex computer still?" "Oh I don't know", she says.
"Could you please look for it, I can fix the keyboard now!"
"Sure. I don't have any interest in using it."
The son thinks it was a long wait but he finally got his inheritance, early.
Turns out alcohol dissolves aluminized surfaces or components. As a result, i have not tried and am not going to try alcohol on the other generation of membranes in the ZX81, Spectrum or the new modern replacements.