Add 1 tablespoon of cornflour and 1 teaspoon of vinegar to 4 tablespoons of water in a cooking pot. Add also 1 teaspoon of glycerin. You can get the glycerine in a pharmacy. Stir the mixture thoroughly with a whisk and heat over medium heat. Always keep stirring. After a few minutes, the mixture becomes thicker. After more or less 10 minutes you have a sticky and glassy substance in your cooking pot. You can then spread this substance on a baking tray or another suitable surface. Wait at least 24 hours for the bioplastic to dry. Then you can pull it off the baking tray. Tip: The more glycerin you take, the softer your bioplastics becomes. If you take less glycerin, the bioplastic will become harder but also more fragile. You can also use cooking oil, instead of glycerin, but it doesn’t work as well.