I carry a little piece of paper in my wallet that has my private key further encrypted by myself, and that encrypted key is used to decrypt other passwords through a private web/mobile app I made. The top encryption key I have is just some sort of simple algebraic mumbo jumbo formula I used to scramble my private key just a bit, and I change it up once in awhile, and have that written down. What's in my memory is how I jumbled it.