I tried silicon spray and lithium grease, but didn't work. Also, the creaking isn't caused at the hinges inside of the earcups, but at the hinge that connects the headband to the earcups. And lubrication won't fix that, there is just too much give there, which causes the creaking. Anytime I move my head I hear the creaking. So it's a bit annoying. Haven't found a way to fix it yet. If I ever find a solution I'll post some pics :)
oh, mine hasn't started creaking at that joint yet, just the pivot inside the cups.