Want to know how to clean up and reconcile your metadata? Check out this site from the Free Your Metadata team. Free Your Metadata is a scientific collaboration between Multimedia Lab (ELIS — Ghent University / IBBT) and MasTIC (Université Libre de Bruxelles).
The goal of the reconciliation step is to connect collection-specific vocabulary to a controlled vocabulary like the Library of Congress Subject Headings (LCSH).
Ultimately, the goal of squeaky clean metadata is interoperability, to prepare data for the Linked Data Cloud. Free your metadata!