What do you do with a tool you no longer use, but can't get rid of?

Been sitting here past midnight with my father's old hand plane on the bench. I don't build much anymore, and when I do, I reach for the power tools like everyone else. But that plane has oil in the wood and his thumbprint worn into the tote. Selling it feels like a betrayal; keeping it feels like a museum. Wondering how the rest of you handle the things you hold but no longer use.