A casing annulus is remediated by inserting a hose into a casing annulus, the hose having a nozzle on its lower end. It comprises loading said input image, converting said input image into a grayscale image i. The threshold voltage can be equal to an average cell voltage of some or all of the fuel cells of the fuel cell stack. The applier is configured to undeploy the attachment mechanism the implantable medical device can be detached from the body tissue.