Tape the pencil-drawn floor plan to the drafting table with drafting tape. Make sure the plans are completely flat and secure to the table. This will keep the plans from moving and ripping when erasing a portion of the drawing.
Place the erasing shield over the drafted template area that needs to be erased. The metal erasing shield will expose only a portion of the area that needs to be erased and protect the other areas that do not need to be changed.
Erase the pencil-drawn area with an eraser or an electric eraser. Carefully move the electric eraser around when using it because keeping it in one place will burn a hole through the paper. The drafted pocket-template area will be erased easily without fear of erasing parts of the pencil-drawn plan that need to be kept.