What an interesting idea: simply cast a candle in a (cut in half) mason jar and voilà! – a mason jar-shaped candle :)
Links:
Mason Jar-Shaped Candle (Craft Of The Day: A Gorgeous Mason Jar Candle)
=> there they link to the original instruction which was during my attempts only readable with a registration at Google
via: 40+ Awesome and Cheap DIY Ways To Recycle Mason Jars – 11. Mason Candle Jars