Fenwicks Waste Pipe & Tank Cleaner's powerful formula cleans and freshens waste tanks and toilet cassettes, removing stubborn stains and unpleasant odours. It's the only product you need to clean the waste system and interior of your caravan or motorhome. How to use: Waste tank (grey & black) Add 100ml of Fenwicks Waste Pipe & Tank Cleaner and 5 litres of warm water to the waste tank, allow to soak on all surfaces, shaking tank occasionally. Rinse thoroughly, repeat if necessary. Black bits To eliminate unsightly bits from the flush system, add 50ml of Fenwicks Waste Pipe & Tank Cleaner and 2 litres of warm water to the flush tank, allow to soak and flush completely through. Blocked pipes Pour 50ml to 100ml of Fenwicks Waste Pipe & Tank Cleaner down the blocked pipe. Leave for a couple of hours to clear. Cleaning Surfaces Dilute 50ml of Fenwicks Waste Pipe & Tank Cleaner to 450ml of water, apply using a trigger spray to all hard surfaces, allow 20 seconds to soak and wipe clear for a clean sanitised finish. Suitable for work tops, fridges, etc as this product leaves a food safe surface.