I used equal amounts of acrylic paint and tacky glue with enough water to make the mixture loose. As you may acrylic craft paint and tacky glue is thick. I just rolled the jar around until the paint mixture covered the entire inside. And put the jars upside down on a old bakers rake to drain the extra out. Allowed to dry and whala reusable pumpkins I’ve been using for several years. For jack o lanterns I used painters tape cut into shapes for eyes and mouths attached to the inside of the jar then added the paint and learned the hard way to gently remove by picking at the tape with an exacto knife while the paint is still damp not wet but still tacky.

My apothecary window at Halloween. That was my first try at about 2 years ago. I may give it another try this year.