Every couple of years, I have a big trawl through the storage tubs, and sell everything that looks like it still works, and which I can identify. Quick photo, list at 99p starting bid plus a couple of quid postage. A lot will sell for that 99p, some will go a bit higher, but some go silly, for no reason I can fathom - I recently sold a 15 year old Roland MIDI synth thing for three times the new price, to a chap in Italy, who was delighted with it, and old Nokia phones and tablets are perennial good sellers.
Be prepared for a couple of buyers complaining that their purchase doesn't work or didn't arrive - just refund them immediately and in full. Life's too short to argue.
Anything that I can't identify goes back in the tubs for the next round in a few years, of course.
This normally nets a few hundred quid, which can of course be spent on new, even more useless, gadgets and cables.