How can I remove a "log lighter" pipe from my fireplace?
You will need two wrenches, one to hold the pipe coming out of the brick to prevent it from turning, and the other to unscrew the log-lighter "air mixing" fitting (the fitting has an adjustable flap that controls the amount of air pulled into the lighter pipe to allow for optimal flame). WD-40 or any other penetrating oil might help, and I would use pipe wrenches as it will probably be stubborn. If you slop a mess of oil around in there you should wipe up the excess before using an ignition source, just in case.