If you have a need to melt down plastic bottles, say to pour moulds for crafts and hobbies, do so outside to prevent any toxic fumes from entering your home. Make sure the bottles are clean and all glue and labels are removed prior to melting. The plastic from the bottles will be hot and runny once melted and should be poured into moulds immediately once melted down. Keep a type B fire extinguisher nearby in case the melting plastic ignites.
Fill the large pot 3/4 full of water and put the two quart pot into the centre, making a double boiler. Bring the water to a boil with an outside heat source.
Remove the bottle cap. Chop the clean bottle up into small pieces with the utility knife. Put on the goggles, mask and gloves. Add small pieces of the plastic into the two quart pot as the water boils in the larger pot.
Swirl the two quart pot in the water so the plastic continues to move. Do not let the plastic sit in one place as this may lead to charring or the plastic igniting. As the plastic pieces begin to melt, add the other pieces of the chopped up bottle.
Watch for the plastic to melt into a gooey soup. When viscous, pour the plastic into the moulds or onto the craft project.
Always wear the safety gear to prevent injury when using a double boiler to melt plastic.