Biodegradable Zero Waste Water Filters. Reuse, then compost. A pack of 4 suits for a 1 Litre jug of water. 4 Filters come in a reusable natural cotton bag. Place filters in a jug or bottle filled with tap water and they will slowly filter out impurities such as chlorine. Reuse in water for two months. After two months, reuse in many ways throughout your home. Place in your fridge to keep produce fresh, place in mouldy kitchen and bathroom corners to remove moisture and smells. Compost at the end of their life. Instructions For Use Use approx: 1 litre jug = 3 - 4 pieces; 2 litre jug = 6 - 8 pieces 1. Wash in running water to remove powder (do not use detergent). 2. Boil for 10 mins in a pan of water to sterilise & allow to cool and dry. 3. Place in a jug and fill with tap water (charcoal may float when new but it will tend to sink after a week or so of use). 4. Leave for 8 hours or more for best results. You can leave it in the fridge to chill if you like. It's then ready to drink. 5. Re-sterilise once a week by repeating step 2. 6. Replace with new charcoal after 2 months approx.