1) Pick a process that coincides with how often you want to clean your desk. In my case, it’s a montly report.
2) Tie that process to a specific username and password that you never use.
3) Pick a password that’s impossible to remember. Write it down on a random piece of paper.*
4) Put the paper on your desk.
5) In a month when you need that password, you have to clean your desk to find it.
6) Repeat step number 3.

* If you had put the password on a postit it’s too easy to cheat by looking for the postit. Although the odds are good that in a month you won’t remember if you wrote it on paper, a postit, the back of your pay stub, or your arm.