A postage metering system that includes a secure metering device coupled to a printer. The printhead is borne by a carriage which is rotatably mounted adjacent an elongate bearing rail wherein the rotated condition of the carriage relative to that rail establishes the desired spacing. If the color change indicates a higher copper concentration than the known test standard, then the fluid is considered inadequate for safe operation and thus recommended for replacement without any further tests. The user may also be alerted if a web page contains embedded code known to be malicious and the order of the search results may be modified based on the embedded code information of the web pages in the results. Also provided are methods of their use for the treatment of an HCV infection in a host in need thereof.