I figure summer is a good time to get some pre season maintenance done on my fireplace. Until now I have always had a chimney sweep clean my masonry flue on my fireplace, but he's since gotten out of the business. So, I went and bought the rods and brush to tackle the project myself. I bought the brush that was the closest fit to my flue, (varies an eighth inch at most). I went to test it out and I only pushed the brush down the flue a foot or so and had one heck of a time reversing it!! For those who clean their own masonry chimney flues how hard should the brush reverse? The last thing I need is a broken plug in my flue.