Yesterday I came across something new (to me) in a NYC bag's nautical hardware. I received a red Companion bag that had fasteners with signature anchors, Talon zipper etc - I wouldn't doubt its authenticity. The leather is in an average condition as expected, I don't think there would be a particular challenge making it look good after dunking and thorough conditioning. The hardware, however, had something I'd never seen before - a layer of red matte, what I thought, base paint under the gold top paint that mostly peeled off. I instantly panicked and tried rubbing it off with a jewelry polishing square. It took some really hard rubbing to see a normal golden brass color underneath. What the hell, I thought, and went to show it to my husband who knows way more about metals than I do. He said this is something called "red rot" that appears on brass surface (which is essentially a copper and zinc alloy) in the corrosion process called "dezincification", when zinc leaches out of metal. That mostly happens due to prolong exposure to oxigen/high humidity and is typically seen in older brass musical instruments. If it could be rubbed off with thorough polishing, that means the corrosion is not deep and the metal parts should be safe for future use as the process would be stopped. I also did a bit of research about the differences in brass alloy and found out that naval (nautical) brass is considered corrosion resistant due to presence of tin that prevents dezincification of parts exposed to water and moisture in the air. So it looks like whoever supplied these lobster claw fasteners and d-rings to Coach used a lower grade alloy, containing little or no tin, which only became obvious after years of use and exposure to elements.
If any of you ever had experience of dealing with red rot, were you able to get rid of it completely, and has it ever come back again?
In the second picture you can see some clean brass on the top after I rubbed off some leftover gold paint and red rot layer.