That's potentially a large amount of passcodes to remember. Here's what you do. Have all the keys in one location, assign it a number. Then you have a spiral or other legal pad. Each page has a number on top. When you take key 45, you log it time and date and if it's in or out. As George Carlin would say, "It's a real simple operation, isn't it? It's low tech shit..." Love that guy