Indoors, pine sap was seldom made into candles. It was unnecessary. A piece of sap cut or pulled from a tree—about the size of a little finger from the tip of it to the knuckle—would burn for longer than an hour. It was laid on something flat that was heatproof, like a carefully chosen rock with a depression in the top of it. A lamp in a seashell would not drip tar on a table or cause the shell to break from the heat. A wick of twisted thread or string was pressed into the sap and lit. The flame would char the wick until it reached the sap and then set it on fire.Text and image from an article about colonial indoor lighting at Colonial American Digressions.