The first thing we did was take stickers and pressed them FIRMLY against the jar. You can do this with hearts or any kind of sticker you would want.
Next, I had them squirt in the paint. I added a tiny bit of water to thin it out. We put plastic wrap over the top and then had the girls swirl the paint around inside. I was thinking these could be used with electric candles inside. If you do that, you’ll want to put a couple coats of paint. This does take a couple days to dry too, and I kept rotating them. You could remove the stickers, but I ended up liking the look of the transparent stickers I chose. I decided to put another vase inside them (it is water soluble paint) and use them as flower vases.