You can pour it hot or cool. I prefer cool only because with the temperature fluctuations in my house I don't have to worry about heating the tops. I just think that tins are adventorous because they can be unpredictable. For me anyway, they start off very cool and don't melt nice and then the end can be scorching hot. It takes alot of trial and error to wick them correctly. Just my opinion, but I would try jars that are the same size from top to bottom and see how that works for you. Just until you get used to how they burn and get the wicking down. Like an inexpensive jelly jar or something. But again, that is just my opinion. Good luck.