While it might seem like a good idea to gift or sell your unused hardware wallet, this is not recommended. There’s always a risk that residual information could be extracted or that the device could be tampered with, potentially scamming an unsuspecting new user.
To ensure peace of mind and eliminate any possibility of exploitation, it's best to either securely store or destroy the hardware wallet. Some hardware wallets, like the Coldcard, provide specific instructions on which components to destroy for safe disposal. Following these guidelines ensures your old hardware wallet cannot be misused.
In summary, the safest approach is to keep your unused hardware wallet in a secure location or destroy it completely.