Locate the end seam of a section of siding. Insert a zip tool underneath the J-channel siding, a couple of inches from the end seam. Do this above the section of siding you want to remove.
Slide the zip tool down the siding's length until you reach the opposite end seam. Pull the zip tool out from underneath the siding.
Lift the loose siding up gently to expose the nailing flange of the piece below it. Remove all the nails holding the siding in place by prying the nailheads up with a flat bar. Be sure to use the flat bar only under the nailheads and not under the siding itself, which may be brittle.
Hold onto the siding's nailing flange. Give the siding a quick downward pull to free the interlocking connection along the bottom edge.
Repeat Steps 1 through 4 to remove as many sections of J-channel vinyl siding as you would like.