I never (well, almost never) clean the tips or nozzles. And I've never seen them slide. Just my experience.
I sold my Phantom rather than going the try different cable route. I'm sure a silver or a gold cable would have brightened them, and maybe even taken away some of the mid thickness that bothered me so much. But it just seemed that spending more money trying blindly to fix an $1800 iem to my specifications made no sense (to me). I bought it to serve as a warmer variant of my Zeus, but found that less than 10% of my music sounded good with it. I liked it, but it didn't suit me. So I sold it. The Zeus XR came with a hybrid cable that was, to my ears, too sibilant and thin. It arrived with a weak spot on one ear wire so it cut out (a lot). When I asked for a replacement EE sent me an Ares. Much better (for me). The Massdrop Zeus also came with a hybrid, which I listened to for 5 minutes and then swapped out for an Ares I had sitting around. Much better. However, I have in the past, with other cheaper iems (<$1K) purchased cables that pleased me immensely. I've had 3 Moon cables, plus a few others. So certainly I'm not against improving sound with a cable swap.