I just got done cutting up a big flail mower pallet with a cordless chainsaw. Big pieces go to the woods. Burning them isn't worth the trouble, since they will vanish in two years. Medium-size pieces to the big landfill that takes construction debris.
The little local dump won't accept construction debris, so the little pieces with nails will either to go the big dump today, or I'll sneak them into the household garbage tomorrow and take them to the little dump.
I don't know the model number of the Harbor Freight magnetic rake, but it's the big one. I don't know if it's as good as the pro rakes, but Project Farm likes it.