Vintage 1970s Automark electric spark plug cleaner with a retro orange plastic case. This runs on 12 volt DC (automotive battery) and has alligator clamps for connecting to the battery terminals. It carries a patent number from 1975.
This cleaner works by sucking up sand and blasting it over the spark plug electrodes. We hooked this to a truck battery and the motor and blower run, but you'll have to provide your own sand. A cup or so from the sand box should work fine.
There is some degrading and age to the rubber spark plug gasket in the top.