Cisca van Sloten ยท Washing with chestnuts, good for the wallet and the environment! No washing active substances, softeners, fillers, fragrances (perfume), bleach and foam regulators will end up in the drain water. The saponin present in the chestnuts will foam as soon as it comes in contact with water. One liter bottle is enough for 12 to 15 washes. And if you miss a nice smell, you can put a few drops of essential oil in the fabric softener bowl. I absolutely love it! How do you make detergent from chestnuts? Cut 10 chestnuts into four, put in liter bottle and fill with water. Shake well and after two days you can use it.