Get a soldering iron, a metal ruler, and cut all the large sections of covering about 1/4 inch from all "inside" corners (like where the stab joins the fuse). Use the soldering iron to melt the existing covering. Do not use shrp blades as they will cut the underlying balsa and weaken it.

Also leave 1/4 inch of covering in all the hinged sections (lke where the ailerons are attached), and any other area where re-covering will be really difficult to get the iron into.

Find a corner flap and pull hard and carefully to remove the covering. Using a covering iron to re-activate the glue may help with the stripping of the covering.

Re-cover, overlapping the places where you left the old covering behind, being careful to cover the old stuff as completely as possible. You will have to be content that a very careful inspection of the plane MAY reveal that it has been recovered.

gus