I quickly pulled the two previous jars from the trash, and searched for a few more in the refrigerator. I emptied the remains of the jars into the trash, and soaked the jars in warm soapy water for about ten minutes. After a quick wash, the product labels came off easily, and I was left with the beginning of the Halloween lab. (Insert evil laugh.)
I rummaged through the gazillion toys in this house, and found a spider, a net, a snake, a bat and a brain eraser. Perfect.
I added an item to each jar, to see which item would look good where. (Keep in mind the item does not have to float or fit perfectly. The snake looks great coiled up. The perception of the spider would be totally different in a larger jar.)