I purchased some "grabbers" and often go near the ponds in my neighborhood to pickup litter.
There are a lot of two liter bottles which are full or half full to be found, normally right near the shore. The first couple of times I found these, I foolishly emptied them (thought this was a good idea since they are so heavy) and along with whatever kind of liquid was inside, AA batteries came out. I vaguely have memories as a child of trying to create "explosives" by putting batteries in a bottle and throwing them (after shaking everything up of course). Not sure if that is what is going on here but if so, kids haven't changed much. I am sure that the kids that put these together later regret it (like around dinner time same day), but couldn't retrieve their device for fear that it might "blow", and so they just have to hope it is deactivated with time.
The item which to me is most baffling which I find in high volumes, is dental flossing sticks. These are commonly found everywhere around the ponds. I don't believe I have ever seen someone using a dental flossing stick in public. I have looked this up and I did find something suggesting that fisherman might use these as an all-purpose tool. Still not sure what this is all about.
The Homeless in my area of town use them and drop them on the street.