If old stuff worked, it'd be proof enough that the hack was effective. I dabbed a bit of Krazy Glue onto the side of my jar, waited for it to dry, then spread on a layer of store-brand cream on ...

Some glues are sticky polymers dissolved in water or another liquid, like common white glue. As the polymers dry, the liquid evaporates and the solid, sticky adhesive stays behind. Other glues help ...