What were we thinking?

I was at the post office today and as I was waiting in line I happened to notice a sign on the wall that read, "Let's Keep The Mail Safe!" Under the caption were various pictures of unsafe items that you shouldn't send in the mail--you know...hazardous chemicals, fire arms, explosives, pressurized canisters. To my relief I did not see any cow patties pictured on the poster...whew!