Biodegradable bamboo charcoal water filters. Place the filters in a jug or bottle filled with tap water and they will slowly filter out impurities such as chlorine and chloramines. Reusable Compostable Zero waste Suitable for a 1 litre jug of water Contents: A pack of 4 in a reusable natural cotton bag.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. Compostable at the end of their life but also can be reused in many useful ways throughout your home.After 2 months of use reuse the filters for mouldy kitchen and bathroom corners, place in the fridge to keep produce fresh, help remove smells from your fridge or bathroom, they can also be used to help remove moisture from damp areas.