It appears Coinbase paper wallet private keys are in a proprietary format, so my “easy” method won’t work. Here are instructions to really trade your Casascius physical Bitcoin for U.S. dollars.
- Obtain the private key. Carefully remove the hologram sticker from the back of the physical coin. A bunch of letters and numbers are printed on the back (example). Those letters and numbers comprise the “private key” for a Bitcoin wallet containing some amount of Bitcoin(s). Whomever possesses this private key may send any fraction (as little as 0.00000001) of the wallet value to another wallet.
- Create a wallet on Blockchain. https://blockchain.info/wallet/new
- Import the Bitcoin to Blockchain. In your Blockchain wallet, click “Import / Export”, then paste the mini private key from your Casascius physical Bitcoin under ”Import Private Key” and click “Add Private Key”.
- Sign up on Coinbase. Use this referral link and I’ll get $5 after you exchange 1 Bitcoin.
- Send the Bitcoin to Coinbase. On Coinbase click “Send/Request”, then “Request Money”. Leave the form blank and just copy the address. In your Blockchain wallet click “Send Money” and use the address you just copied.
- Sell your Bitcoin for USD. This part is pretty straightforward. Click on Buy/Sell to sell your Bitcoin and transfer the USD to your bank account.