an armored knight, all layered and plated and buckled in, would have a fairly noticeable odor (unless they were being compared with peasants, cities with streets that were almost liquid shit, and a time long before proper hygiene.
Heavy leather straps long soaked in sweat, reinforced and padded clothing, reinforced with scraps of chain or perhaps covered with an overlayer of chainmail, the various imperfectly refined greases and oils to keep these parts rust free..
But whatever you do, don't ask the noble knight "What the hell is that stench?!"