Found in storage.

Hello. I Found this thing and was idly about to throw/give it away on a facebook group. An old keepsake from my dad.

It got so much immediate attention that I had to double back and have a better look.

Before I airbrush the dust away, can anyone give me advice? Somebody offered 7000 dollars for it but I neither want to oversell old junk nor undersell myself.

And, just to be sure, how would I best go about plugging it in and trying? Are modern sockets safe for such an old device?