Jade and green

1. download electrum 2. unplug your router 3. create a new wallet 4. export the pubkey to your mobile wallet of choice 5. delete the electrum file 6. plug your router back in 7. congratulations you have a completely Free ($$$) and FOSS cold storage wallet without having to buy any fancy hardware !

this too:

On Making High-Entropy Paper Wallets | Contravex: Essais de Pete D.

Deleting the file isnt enough.

Please free to add any extra information that could be useful to the crowd!

A key that ever existed on a computer that is later connected to the internet isnt provably better than a hot wallet.

I agree! One level up is to boot a live linux disto on a diskless offline PC with a bitcoin wallet included - like

Tails - Home

for example but still not good enough, only a bit better

I'll try this when I have enought sats

Doesn’t hurt to practice with a small amount before you have large sats on the line! It’s pretty risky for your first time messing with cold storage to be with a meaningful chunk.. mistakes do happen