I have a 1920's frame house with a chimney along one end of the exterior wall. I was installing an HDTV over the fireplace this weekend, and when I drilled the bracket into the studs, the drill bit retained some pungent, yellow sticky wood upon backing out of the hole, almost seemed like sap but I am assuming it is creosote. This was only at the 2 holes within the stud that falls in line with the chimney itself, the one alongside it had dry regular redwood shavings. Unless framing members were treated with creosote back then, I can only assume it is buildup from when the fireplace was wood burning. At some point a gas fireplace insert was installed, works fine with no apparent heat at the wall surrounding the chimney. I am wondering if there is any danger in this buildup living within the wall farming, even with the unit having it's own surround and not being wood burning. Any insight would be greatly appreciated, thanks.