Storage of MFCoin
The safest way to store MFCoin is the PC wallet. Before using the wallet, you need to encrypt it and do not forget to save private keys and backups of "wallet.dat". (There is also a safer, but more radical method of storage Paper wallet)
Storage of passwords
As you know, you need to have as complex password as as possible. But this is not enough, normally you have many accounts to different services and it is not safe to use same password to all of them bu it is also impossible to remember so many different passwords. The best solution will be to store passwords in 7-zip archive using AES encryption with password that consists of not less than 9 symbols and this password written down on paper sheet.