Many businesses offer cash for suggestions, put a suggestion box near the canteen, and wonder why most of the suggestions are physically impossible, morally debatable, and often both.
In the end, successful suggestion programs offer the reward of personal satisfaction and recognition to those making them, any financial incentive is usually secondary. The $50 in the paypacket for a successful suggestion is nice, usually appreciated, but not the reason the suggestion was made.
People who are members of a “community” and a workplace is a community, normally want to contribute to that community, unless it is dysfunctional in some fundamental way, and those contributions build connections and mutual obligations, that are the glue of any community.
Many suggestions will be worthless, but offering recognition and feedback to all offerings creates a sense of personal connection. Create that, and the suggestions will increase in value progressively, and ultimately, very few will have anything to do with deviant behavior, and you will quickly be able to do away with the anonymous box, and have the feedback directly, person to person.