Discover the world of Fing"rs Crayola Color Changing Stick-On Nails. When exposed to sun, watch the magic color appear. Fing"rs Crayola Color Changing Stick-On Nails: Changes color in the sun24 stick-on nails Step 1: Buff, clean And dry nail before applying artificial nails. Step 2: Select a nail that closely matches your natural nail size. Step 3: Place Stick-On nails at the base of the cuticle And firmly press onto your own nail.