Step 2. Lay the watch, crystal face down, on a soft towel. Carefully and gently pry the back off the watch. There is a small pry tab on this particular Casio model. Use a small straight-blade screwdriver for carefully prying this cover up. The link adjacent to the pry tab acts as a fulcrum for raising the cover. Once the cover has been raised, slip a fingernail under the cover and remove it.