You can put in Polkadot Vault (rebranded from Parity Signer) on an outdated smartphone reset to manufacturing facility defaults, which you'll continue to keep in plane method. Using this method, you can convert your aged phone into a chilly storage wallet. I was initially hesitant to try psilocybin, but Polkadot https://alexisjiigm.blogunok.com/30517833/about-official-polkadot-website