Hi, the stencils are made out of plastic and do not have adhesive on the back. Many people choose to use a spray adhesive (very lightly sprayed every few times you move the stencil). The trick is to not apply too heavy of a coat of paint (whether you roll with a sponge roller or use a stencil brush) and you will avoid heavy bleeding under the stencil. You may need to wipe/wash the back side every once and a while but not between every use.

Hope this helps!

Peg