Pot hunters are individuals who excavate sites unsystematically in order to loot them of their contents. They do this either to enhance their personal collections, or to sell everything except the prize pieces. This activity is very destructive to archaeological sites, and on public lands it is actually illegal to excavate without a permit from the State Archaeologist . In other words we try to find out about people in the past from what they left after them. Only by accident.
Archaeology is interested in human beings who lived in former ages.
A beachgoer spots a stone tool in a sandy cliff-face. A bulldozer operator sees charcoal stains in a cellar-hole he just excavated for a new building. An historian's work mentions a place where Native Americans camped to fish every year. I found an arrowhead under my tomato plants. If you do, you will undoubtedly destroy more information than you will find.