Beginner running a full node (Bitcoin Core): Is there a command to get a wallet containing passwords from an external USB stick? And how to clean a paper wallet?

I need help with:

• (Linux) What console command (Linux) to use to import an external USB stick wallet (with passphrase) created in an older version of Bitcoin Core?

• How do I clean my paper wallet (including passwords)?

For the first time, I would like to transfer from my Bitcoin Core wallet to an exchange and sell it.