Anybody use old pallets for firewood?

I burn a lot of pallets. Mostly heavy duty 36x48(fit in HHR) OAK from forklift supply. I
had another source from a floor coating company, but they were too messy.
On average, it takes me 3 minutes with a circular saw to cut the slats out a a pallet.
I leave the rails for the chop saw. In less than 2 hours I can "butcher up" about 15 pallets,
Thats from dragging the saws and stuff out of the shed, to blowing and sweeping the driveway
for nails when i'm done.