I am redoing the flooring in my basement and removed a built-in toy chest. I disassembled the chest and the floor 2x4's are attached to the cement with large nails. If I had to guess on gauge I'd say around 0. I split the 2x4's and have removed them, however I have been unable to remove these nails. I've tried hitting them from side to side with a hammer to loosen them, but after about 20 minutes have no sign of them budging.
Is there a secret to removing these? I don't have an angle grinder so I'm hoping I can remove them without having to cut them off.