I do not add anything to the wax, it burns great for me in the 1/2 pt. jj. I use the 51-32-18 Z in the jj and no problems! This jar does have a smaller opening but not much, I got it from the jar store. And I don't fill it with wax, just to the top of the widest part, know what I mean? I saw in an old post where someone used this jar and had to double wick, thats why I tried it. But I am going to go back to testing single wicks. I have Zinc, Eco and LX sample packs of wicks, but I'm not sure what the difference is in all of them. The LX, I'm thinking, didn't work at all in this jar. The Zinc 60-44-18 made the jar black, ECO 10 left soot on jar and Eco 12 did ok..but not as good as I like it to be. I was about ready to give up, but I'd really like to use these for Xmas, just because they are prettier than just a plain JJ. Thanks so much for your help, any other ideas? Dee