A few years ago, my parents were downsizing and I wanted to find a respectful home for some of the amazing stuff he had in the garage, so we donated to the Vintage Computer Foundation: https://vcfed.org/artifact-donations/.

They don't take everything, but it felt better to give this to them than to have folks who didn't know these systems' import taking them to the dump.

Also highly recommend attending Vintage Computer Festival events if you get the chance.