One of the most interesting things about raccoons is the way they sometimes dunk things in the water, usually food. This is usually called "washing their food", even though they aren't washing, and it isn't always food!
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C.Fazalmahjid under Creative Commons open license
Raccoons have millions of nerve endings in their paws. About two thirds of the part of their brain that processes sensory information is devoted to processing information from their paws. So, by holding and manipulating an object with their paws, they can get an idea of what it is, that is almost as good as we would get by looking at it! Putting the item in the water makes it easier to feel the details of the object because it reduces friction, and softens the skin on their paws to make them more sensitive.
Even when there is no water available, raccoons frequently pick up objects and handle them, to help them understand what they are. Just as we sometimes look at things and smell them at the same time to help us understand what they are, raccoons will look at something and handle it at the same time to help understand what it is.
The other thing that people most commonly associate with raccoons is disease. While cats or dogs get more diseases than raccoons get, we still fear that raccoons somehow "carry" disease.