When canvas is stretched over wooden stretcher bars, it is secured onto the wood with staples. Regular canvas is stapled on the sides, made to be placed in frames once painted, thus hiding the staples from view. A gallery canvas, however, is made with the staples in the back; this way the artist can paint onto the sides and have the painting "wrap-around" without the need of a frame. The staples used in canvas are "heavy duty" and more secure than regular office staples. Removing the staples takes care and precision to avoid damaging the canvas.
Things You'll Need
Towel or soft surface
Upholstery staple remover or flat-head screwdriver
Small rubber mallet
Place a towel down on a table or floor to create a soft surface where the painting can be placed while removing the staples.
Lay the canvas down on the towel if the staples are in the back. If the staples are on the side, place the canvas on its side and work on one side at a time.
Pry your staple remover or flat-head screwdriver gently under the first staple. Upholstery staple removers have a forked point. If the staple is tightly adjoined to the canvas and wood, you may need to "dig" under the staple in order to get the staple remover under the staple. The wood used in stretcher bars is soft, so pushing down under the staple should not be a problem.
Push the handle of the staple remover/screwdriver down carefully to help loosen the staple. If the staple is tight, lightly tap the handle of the remover with a rubber mallet.
Use needle-nose pliers to pull the staple out completely.
Remove all of the staples in this way until the canvas can be lifted off the stretcher bars.