Good ways to thank my local police department?

I don't know any of them personally, but I live in a really nice and safe town and thank my lucky stars every day that I don't have to worry about being murdered walking down the street the 5 minutes it takes me to get to Safeway (this sense of safety is completely absent in so many cities in the U.S.).

The safety of my town is in part due to the people, but also because of the efforts of our P.D. because it is a lower middle class blue-collar working-man/woman's town and there is the fair share of undesirables. It attracts mostly people who work hard all day and are super tired at the end of the day, but every so often, the town gets a household of people who don't want to work and would rather survive off government assistance, and since they have nothing better to do, they cause trouble.

Our P.D. works day and night to keep these people in check. How can I thank them if I don't know any of them. I know that they're wary of any unsealed food because of douchebags, so that's kind of off the table.