Historical Trash. Is this term something you've heard of before? If you haven't heard it before, that's okay, many haven't!
To start this conversation off, it is important to know that all artifacts (50 years or older) on public lands are protected by law and it is best to not collect anything unless directed by the land manager associated with the area you are visiting and picking up litter at.
Common kinds of historical "trash" you mind find include: glass bottles, tin cans, tin containers, machinery, nails, railroad ties or spikes, ceramics, pottery, firearms and old bullets or cartridges, bricks, silver, lanterns, and more.
(Image by the National Park Service)
According to NPS.gov, "Archaeological and historic sites contain artifacts that tell a story of how people used that location on the landscape. The association of an artifact to a location, or context, is directly linked with the human activities on the site. Knowing the context of the object is crucial to determining what human activities took place on the site, why this object was used there, and how it ended up in the place and condition in which it is found. When the inhabitants are no longer around to ask, the only way to determine and interpret the questions of "what, why, and how" lies in finding and recording the context, as well as in recovering the objects."
"In fact, the context is more important than the object itself. Only someone trained in identifying the age of items in a trash pile is really able to distinguish between something significant and something that belongs in the landfill. I have looked over numerous piles of cans, bottles, broken pottery, wire and miscellaneous metal over the past twenty plus years and have yet to find something in the pile that can’t tell me how old the stuff is, or more importantly, learn something about the people who lived on the site from the things they left behind. The importance is the context from which the objects came. If we lose the context, then we probably do have just a pile of trash."
The State Historic Preservation Office of Nevada shares that "you can very generally tell historic trash from modern trash by looking for key indicators such as corrosion, discoloration, and how the object was constructed. Some common examples are iron corrosion on the cans, how cans are opened, opalescence on the bottles, and glass color."
There is also this incredibly helpful and insightful guide created by BLM.gov that educates on the different kinds of historical trash you may find, what they look like based on age, how old items are based on their sizes or shape and more.
You can watch this short educational video by Conservation Lands Foundation on Historical Trash as well.