When you decide to stop using a particular Mycelium wallet instance, simply deleting the app is not the most secure method. The recommended process is to first ensure you have a verified backup of your seed phrase. Then, transfer all funds from the old wallet to a new receive address in your new wallet (if you are migrating). Once the balance is zero, you can perform a factory reset on the Android device to securely wipe all data. For maximum security, especially on an older device, physical destruction of the storage chip is the only way to be absolutely certain the data is irrecoverable. The mycelium wallet’s design ensures that with the funds moved and the seed phrase secure, the old wallet poses no risk, but proper device disposal is the final step in responsible key management.