Rant: Spotted a giant bird nest during my sweep yesterday
I was cleaning a chimney with bad draft. My inspection camera found a nest jammed in the flue. I grabbed a rod and a bag to get it out without a mess. How do you deal with nests?
That rod method can backfire, push stuff deeper into the flue. A chimney brush with stiff bristles works better for a jammed nest. Attach it to rods and scrub it down into your bag at the bottom. The key is breaking it apart without shoving it up into the smoke shelf.
My cousin in Vermont tried that rod trick once. He ended up with so much debris in his smoke shelf it looked like a bird condo. Your brush method sounds like a way to avoid hosting unwanted guests. I guess the key is to not turn your chimney into a storage unit. Some lessons are learned the hard way, usually with a lot of sweeping.