Step 1. Wear your PPE Step 2. in 5L of water Add 200g of caustic soda and stir Step 3. Add soda ash 150g and stir Step 4. Add sodium sulphate 100g and stir Step 5. Add Sea Salt 150g and stir Step 6. Add Chlorine 250g and stir Step 7. Set mixture aside for 7 days Step 8. Sieve out the clear liquid and use residue for cleaning black stains on pots, toilet/kitchen sink and bowl, also effective for removing tough brown stains in the toilets. If you enjoy my tutorials, please you can support by ; fol