In high security/value scenarios where you need a fully isolated deployment of YWallet, you can use Ywallet.iso a live CD/USB with a barebone Linux and YWallet pre-installed.
Ywallet.iso is a ISO image that you can burn to a CD or install on a USB drive, and then boot from it. It is meant to be used as a offline signer. As such, there is no networking capabilities and no persistent state.
When you shutdown the machine, your accounts are deleted.