Get a journal, write stuff in there, and lock it up in a box and eat the key.
You know exactly how to get the key back.
This is probably a better idea, to be honest.
Especially if you're able to look after an actual physical copy and keep it safe and hidden.
Plus, it's much safer to keep a physical copy in case you have to wipe your memory, for what ever reason, or if you accidentally lose the file.
That is unless you're able to keep it backupped somewhere else.
I'd just suggest keeping a hardcopy or keeping it on an online storage sort of thing, that you can keep passworded. So long as you can remember that password, of course.
