Kitchen Waste: Recycling Used Cooking Oil

After I cooking on my own, ehem like adult for 6 months, I just realised that we, Indonesians use too many oil for cooking. Indonesians love deep frying food. Tempe goreng. Tahu Goreng. Bala-bala. Kerupuk. You named it.

Cooking Oil Waste

Indonesian goverment made a list nine staple ingredients to indonesian, called sembako. Cooking oil is one of ingredients that they mentioned because we like to deep frying food as a side dish in our meal.

In average, Indonesians consumed 10,72 liter/capita/year (source) means that we need a lot of oil and we make lot of waste as well. We usually use the deep frying oil until 7-10 times or as long as it still looks clear, odorless, we will keep gonna use it for next frying. But when it turned darker and start to smell different, we prefer to use new oil.

The thing is handle used oil cooking is bit complicated. We can not just throwing away the oil because it will be block our plumbing or do some harm into our soil. Some people in my neighbourhood start to sell the oil to some company that will use it as biofuel. But if you living in a small city or somewhere that company can’t take your used cooking oil, it will better if you can recycle your own waste.

I tried to looking up how to recycle it in more economical way. Then I found it that can be used as a soap. I strongly recommend you not to use it as soap for body but for washing your napkins or something else. But if you never make a soap n your own, please read carefully my step-to-step direction.

Recycling Cooking Oil

One of the methode to manage your used cooking oil is turn it to a soap. Since we will use used cooking oil, the soap is not for your shower time. It will be good as cleaning soap.

Making soap is scientific methode. It is chemical reaction that can be measured. If you try to recycle soap within this recipe, you need to be sure that everything is measured right. Much better if you have digital scale that as precise as 0.00.

Safety Guide Oil Soap Making

Since we will make something with corrosive chemical stuffs, called lye, please watch this safety guide carefully.


  • 6-7 wood charcoal
  • 450ml used oil
  • 70gr lye
  • 190gr distilled water, I added pandan/lemongrass as scented.
  • 2% parfume/essential oil (optional)


  1. Heat up your charcoal into red. Put it directly to your oil. The charcoal will absorb the toxic residue of your oil. Let it sit at least 24 hours. Filter your oil from charcoal flakes.
  2. Weigh out your water. Add your lye gradually and stir it gently. Be careful because it is dangerous. Let it cool down until reach 33-35°C
  3. Add your lye liquid to the oil. Stir it until it reach trace. It will be super quick if you use a hand blender. But if you use ballon whisk, it will take 10-30 minutes depends on your saltiness oil level. Since you use the used cooking oil, it means that your oil highly possible to get some salt, which is help to hardened the soap.
  4. When you get the trace phase (like ribbon stage in cake batter), your soap mixture is ready to pour into the mold. If you use any perfume, you can add your pafume before you pour into the mold and stir it until totally mixed.
  5. After 24 hours (can be faster because the salt), you can unmold the soap and cut it. Keep the soap in cool with good air circulation, it called curing process for 4-6weeks before use it.

Happy soaping recyling!