I started the faux mercury glass project before we left for So Cal, but finished them up the other day. At least I think they're finished. I have not decided whether or not to paint the tops.
Yes, these are Yankee Candle jars, wax removed by setting the jars in a pot of hot water, cleaned with Goo Gone and alcohol. There are tons of tutorials out there for how to make this faux mercury glass, I used this one. Key ingredients are a mister with half water and half vinegar, and Krylon Looking Glass paint, found at the local Orchard Supply Hardware.
Also good to have a covered surface, gloves and a paper towel.
I'm not quite sure I'm getting the exact effect, as it's difficult to control the spray and the running of the droplets, but I think they look pretty cool. Not sure yet what I am going to do with them.