We own a 1790's house with original wooden floors. Due to the age of the house the wide wooden plank floors upstairs need work. It looks like they had never been varnished or anything like that. The floor just looks old and worn. The boards are not level, curved a bit in some spots, some move up and down, and have spaces in between the boards that vary in depth and width.
Any and all help as to how to restore them, what to use and how to do it would be greatly appreciated.