I have a set of cables that I've been using to connect my gear together. I've been using them for at least 10 years. The plugs are dull in finish at this point, but otherwise they've been solid. But while I was messing around trying different things, I grabbed my new cables that had shinny plugs, and to my surprise, there was a big difference in highend response, and clarity. I wasn't looking to hear a difference. It just made itself know on it's own. I even A/B'ed them to check, and the result was the same. This must affect tube sockets and pins that are dull and tarnished over time as well. I'd hate to throw away seemingly good cables, but tone is tone. I'll need to pickup a bore brush, and scrub out my jacks too.