I never thought of having to clean out the port, glad to know that tip. I have spare batteries and one wouldn't start charging. I finally took my fingernail and just gently rubbed along the copper connections and, voila, it started charging the second I plugged it in. Hope one of these suggestions fixes your problem.
well it resolved itself and not in a good way. Today the phone just refused to acknowledge the insertion of any usb device, even the docks which seemed to be always the charger of last resort.
Fortunately I took the Best Buy insurance and stopped by the store today. The associate there told me this happens on phones that charge through usb more than you would think, and the ports don't hold up to the rigors as well as they should. He showed my how "loose" the port had become. If you are having trouble I would investigate service to the port sooner rather than later if you can.