How should I handle a landlord/roommate leaving my rent checks lying around after depositing it via Chase snap app?

He’s actually one of the coolest people I know. The only issue is that he is one of the most irresponsible people I have ever met.

I already brought it up, but this is going to keep happening again.
He just doesn’t care about anything. Again, he is a really cool/nice person but I really need a solution.

Cash? money order? are those my only options pretty much? I don’t want someone doing anything funny with my checks/personal info.