I put all my passwords in a text document, then print it on a little strip of paper and shove it up my ass. Whenever I take a crap, I dig it out from the turds and try to memorise some of them again. Then I shove it back up there where noone else can find my data and I won't lose it.
Forgot to mention I delete the text document and set fire to the computer's hard drive. The passwords are only ever in my ass, with the rest of my personal shit.