They can also be turned inside out to yield fingerprints from the inside surfaces. Leather gloves can be treated in the same manner. Even cloth gloves, such as mittens, can leave a distinctive print that can be traced back to the mitten that made it. Prints are left on a surface because we are constantly secreting water and body oils and other compounds through our pores. This material is left on the surface we touch in the form of a fingerprint.
Different surfaces require different techniques for developing prints.
In the movies, you usually see detectives with brushes. They are powder processing the prints. Minute particles of powder cling to the print residue as the brush passes over it. The print is then lifted with tape. Another process involves fuming.