Take a spare phone put a wallet on it (centbee, handcash, whatever) dump all but the essentials off the phone, send your BSV to that wallet, then turn off the wifi then turn off the phone (cheap "cold" storage). When you want to top up your moneybutton or wallet on your primary phone, turn it back on - send it to yourself then turn it all back off again.
Take a spare phone put a wallet on it (centbee, handcash, whatever) dump all but the essentials off the phone, send your BSV to that wallet, then turn off the wifi then turn off the phone (cheap "cold" storage). When you want to top up your moneybutton or wallet on your primary phone, turn it back on - send it to yourself then turn it all back off again.