LINCOLN -- Firefighters spent much of the 4th of July battling two Lincoln house fires. Around 1:45pm Thursday, Lincoln Fire Rescue was sent out to 3474 East Pershing Road when a neighbor saw the roof of a guest house on fire. It took 30 minutes for the fire to be put out. Fortunately, no one was home at the time. Fire Inspector Donald Gross says an artillery shell firework is to blame and the investigation continues. About two hours later, sparks from a firework touched off some recycle materials on fire at a southeast Lincoln home. Firefighters were called to 7910 Thornview Road on a garage fire that totaled two cars and left smoke damage throughout the home. No one was hurt.