The Weatherproof Direct Thermal (DW) material is meant for short term applications and will darken if exposed to consistent heat. If you have access to a thermal transfer printer, the Weatherproof Thermal Transfer (TW) may be a better option. Thermal transfer printing uses a thermal ribbon instead of direct heat so it is less likely to darken over time. Most customers will use our inkjet and laser materials for candle jar labels. Below is a link to common sizes used for candles along with the inkjet and laser material options: https://www.onlinelabels.com/uses/candle-labels You're welcome to visit the link below to our Sample Request page if you'd like to test any of these products with your candle jars. https://www.onlinelabels.com/samples