Step 1
Open https://bitaddress.org

Step 2
Right click and save as to your desktop
Save as a html file in your downloads folder or any other folder

Step 3
Disconnect Internet

Step 4
Double click and open the saved HTML file in your downloads folder in any internet browser like chrome or firefox
The address will be something like this
file:///Users/yourusername/Downloads/bitaddress.org.html

Step 5
Randomly move mouse and use some random keystrokes and generate a bitcoin address

Step 6
Take a printout of the private key and the public key with the QR codes

Step 7
Store the printout in multiple locations

Step 8
Use the QR of the Public key to accept bitcoin to your address which was never connected to internet at all

Step 9
Import the old private key to a wallet like Electrum wallet which allows to import private key
Spend from that wallet.
Repeat Step 1 to Step 8 to transfer the remaining bitcoin to a newly generated wallet.