1) Using pincer pliers, carefully remove cap from highlighter and remove ink cartridge (looks like a felt stick), then drop in jar filled with hot water. The water will help dissolve the ink inside the highlighter. Close the jar and shake it. This will help loosen any ink inside the cartridge, and help to start the flow into the water.
2) Let the cartridge sit in the water for 4 – 6 hours.
If you use a glow stick, just drop it in without cracking, as the inside of glow sticks could be toxic.
3) Add Halloween store props -- bones, spiders, fingers, etc... If you want the jars to really glow, you place them under a black light.
Check out more fun DIY projects at the Home & Family Pinterest Page