Sculpture supply companies offer a wide range of materials for casting objects and making moulds for home decor objects. While you can generally remove your cast models from flexible moulds without much trouble, non-flexible moulds may require a release agent to help you free your sculpture. A variety of commercial products are available for this purpose, but you also can make your own release agent. Common lubricating substances like petroleum jelly and vegetable oil often do the job at a fraction of the cost of speciality mould release agents.
Pour cooking oil into a spray bottle. Use a funnel to avoid spilling excess oil. Wash the oil off the funnel with soap and hot water.
Do not add more cooking oil than you will use within the next few months. Once the bottle has been opened, cooking oil will turn rancid within approximately six months. You can extend the shelf life of your oil by storing it in the refrigerator.
Add a few drops of clove oil to the vegetable oil. This will help to inhibit mould and mildew from forming on your casting mould. Some moisture-containing casting materials like plaster and alginate have a tendency to develop mould.