Use the Dremel tool in order to clear the old paint from the drive of the screw on the boards previously marked.

The drive of the screw is where the screwdriver will fit.

Use the electric screwdriver in order to remove the old nails.

Once all the nails are out you can lift the board out and sweep any rotted wood or debris from where the boards were.

The nails may be rusted, make sure not to leave them where you may step on them.