I've only had my crossfire a couple of months. Mine had an issue where my phone charger blinked in and out. I looked in the socket and here is what I found.

It's pretty rusty if you zoom in. I cleaned it with a glass fiber pen. No risk of metal shorting it out.

Then after the contact in the center was throughly buffed with the glass fiber pen, I put a couple of drops of DeoxIT D5 electronic connections improver on it.

the phone charger is 💯% reliable now. I hope this helps someone else.

 

Great Idea and very helpful! I like that glass fiber pen. If I had known about it, I would have used it.
I cleaned mine with some fiber optic cleaning swabs and contact cleaner. They're like Q-tips but they leave no fuzz.