There is an electrical outlet in a room in my house giving off a strange smell. It smells kindof burnt? It happens almost immediately when something is plugged in/turned on and I promptly turn off/unplug every time so I don't know what might happen if left on/plugged in for an extended period of time (and the outlet is in my young daughter's bedroom so I'm not too inclined to find out). If something is plugged in and off (like a lamp in the off position), the smell does not happen. But if it's plugged in and turned on (lamp turned on or something like an alarm clock that has no on/off switch and is thus always "on"), the smell comes within about 30-60 seconds and is quite strong. We've tested this on a number of different things to conclude it's the outlet and not the thing being plugged in. My husband replaced the receptacle and cleaned the dust & debris out of the box, but the problem persists. He noted that there was no discoloration of the receptacle, wires, or the box, though there did appear to be some mild corrosion on the wires he believed to be the result of arcing. The thing was old, but otherwise appeared normal.
Any ideas what the problem could be and how we can fix it?