There was a motorcycle parade today, and they were tossing candy from the motorcycles for the kids, and strings of beads. Nephew got a string of beads, and all the moms split up the candy to share among the kids.
We got a great big pile. Nephew found one piece that he really really wanted, and I checked it to make sure it was wrapped properly, and then (since it was) let him have it.
Then I had him help me sort the candy into two categories: Safe, which we put in a Tupperware box, and Unsafe, which we threw directly in the trash. I explained briefly that bad stuff could get in candy that wasn't wrapped in the right way, and so whenever we got some of that from strangers, we had to throw it out, since we didn't know where it had been.
There was a huge pile left when we were done, so he was satisfied. He's got more of a clue about candy safety now.