A method and associated apparatus for cleaning a secure instrument including a substrate, visual data and a security feature, including exposing the secure instrument to ozone sufficient to clean the substrate and not compromise the security feature and the visual data, where to clean the substrate includes to remove one or more substances from the substrate into the ozone or to chemically alter the one or more substances in or on the substrate such that exposing the secure instrument to a supercritical fluid removes the one or more substances.
