Cover the ground along the base of the wall with large tarps or drop cloths to catch any falling debris from the removal process. Put on a pair of safety goggles and work gloves as personal protection from siding pieces.
Place a ladder against the side of the structure so that you can reach the upper rows of siding. Slide the end of a flat pry bar beneath a shingle in the center of the top row of siding pieces until the fulcrum of the bar is on both sides of a nail. Apply pressure to the bar to pull the shingle away from the wall, aiding the process by grasping and pulling with your gloved hand as well.
Remove the nails remaining in the house sheathing once the shingle is gone, using the teardrop-shaped hole located in the end of the pry bar. Slip the hole over the nail, and pull the nail free with the hole’s edge.
Move over to the next shingle, and repeat the removal process. Work your way fully down the row until you remove the entire length. This will reveal the nail locations for the next row of shingles beneath the top row.
Work your way down the wall row by row until you’ve cleared the entire wall.