Below is a list of Grease Kettles manufacturers from Valley Forge, Pennsylvania. Grease kettles are pressurized tanks that are used to manufacture grease, a type of lubricant. They steam heat, mix and then cool the ingredients used to make lubricating grease, a substance widely used in industrial manufacturing processes. Grease refers to a semi-solid lubricant (not the fat from animals in food) that has a higher viscosity than oil. It is usually made from calcium, sodium or lithium soap and mixed with mineral or vegetable oil.