I live in MN, it's cold. This year has been especially bad and my sewer vent is freezing up every 2-3 days. So far, I have climbed the roof and used a broom handle to punch through the frost dome that has formed. I do believe I have a cleanout in my basement directly below, can I safely re-route my (electric) dryer vent up the pipe to thaw it out? If not, how about a 2-3 foot section of heat tape dropped into the sewer vent from the roof? Is that a fire hazard, or s there a low wattage version that is safer? Any help would be greatly appreciated!