To many of you, this is so obvious it's gonna be painful, but until I learned it a while back, I was pulling nails the hard way. You gotta learn sometime, this might just be it.
Way back when, after we got our first cat's paw (tool for digging out nails embedded in wood, like after that time we had to move the entire wetwall 4" over in the kitchen... ah, memories..... :-) well, I realized that once you get the head of a 4" nail 'above-ground' so you can get at it with a crowbar or hammer, but once you got the nail about halfway out, it was just pure muscle trying to squeak it out the rest of the way.
The the hubby showed me a trick: Leverage.
Pulling out nails is so easy now. Of course, I've had LOTS of practice.
1> You get the nail halfway out. You get stuck.
2> You reach down and find a block of 2x4. They're everywhere.
Stick the block of wood next to the nail, and put the hammer on top and pull the nail using this block as the pressure surface.
3> Nail pulls out SOOO easily.
OK, lesson over.