I do Adopt-A-Highway cleanup on our town's only main road once a month with the Venturing Crew.
Around here, in redneck country, the most common litter item is chewing tobacco containers, although Svenhard's wrappers and dirty diapers (along with the ever-present soda pop cans and paper/styrofoam cups) also abound. We've found baby shoes, yards and yards of rope, and empty chicken or cattle feed bags. Once, we found the plastic packaging to a Nintedo system, but alas, no Nintendo. One girl even found a cell phone. We managed to return it to its owner. She said she had put it on he hood of the car to get her child in, and forgot the phone was there. When she took off, away it flew. She sure was glad to get it back!

I don't know why people litter or otherwise deface areas. It's really not that hard to put the garbage in your car and throw it out when you get home.

La"I don't understand Newton's Rings, either, but that's another post"Zorra