Inside of a gas lantern is a small mantle that looks like a small net bag. The mantle is usually made from artificial silk or rayon fabric. The fabric is completely soaked with an earth oxide. Thorium is an example of a rare earth oxide that can be used to saturate the fabric. The mantle is then placed inside of the lantern. When the lantern is heated, the fabric on the mantle burns off. Only the ash containing the earth oxide is left behind. This earth oxide is what glows brightly inside the lantern.
Select a small piece of silk fabric and handstitch it into a baby sock.
Soak the silk sock in thorium earth oxide until saturated using a chemical dip.
Unscrew the cover of the gas lantern. Remove the cover and globe that surrounds the old mantle inside.
Tie the new mantle into place on the gas outlet pipe.
Pressurise the gas tank and hold a match near the mantle to make sure it will burn.
Replace the glass globe and cover the lantern as the mantle begins to glow.
The earth oxide chemical dip is still a well-kept secret in the industry and generally cannot be done at home.
When working with earth metals and lanterns, wear eye protection and gloves.