In response to the "WE ARE ..." month long awareness campaign to clean up the campus particularly when it comes to newspaper littering, I think I have an alternative idea.
Instead of showing people what to do, why don't you do something that actually makes people change, such as start charging a littering fine.
Something like a $50 fine should change people's behavior and make them recycle instead of leaving their trash there as a "present" to the custodial staff.