100 year old houses are relatively convenient to take apart because the original structure contains no screws. Two by fours will come out just by being banged with a sledgehammer if there are no screws. My friend Ed and I saved about 50 2x4 studs from the old pink house that stood at 9805 - 84th Avenue until last week.
They are much closer to 4" by 2" than modern-day studs, and they do sustain a bit of damage coming out. So, they would only be good for firewood if I didn't have such an eco-minded builder. His guys are used to him asking them to frame with reused lumber, so these bad boys will get used one way or another.
The picture above shows reclaimed doors, cedar siding, fir flooring (under the pink siding on the left), doors, and the 2x4s.
Right before demolition, we also pulled out six or seven good double-paned windows (for making cold frames with), the exterior doors, and the kitchen cupboards from the house. The garage is full. Now it's time to start installing all of this reclaimed material. That's the hard part.
Thanks for the help Ed!