Removes all scale including the hard to remove silica scale and calcium scales. “Magic” is a non-abrasive powder that will not damage glass when used according to directions. Use wet a non-scratch scourer sponge. Scale that appears on shower screens predominantly, but also other glass, is often characterised as calcium scale. The reality is a little different. The scale appears to be a matrix of calcium and silica, so where there is a lot of silica in the water, cleaning is almost impossible, as silica is relatively inert. The Magic Kleen contains a soft abrasive, and a safe powdered acid . The abrasive exposes the matrix, allowing the active ingredient to attack the calcium component, and at this stage the silica simply collapses.   1. Simply wet a non-scratch scourer sponge (usually these are coloured white). If progress is slow because of heavy build up,, don’t be afraid to use a harder scourer say a green nylon but check on an inconspicuous area first. 2. Shake a little of the powder onto the scourer sponge or dip onto the surface of the powder from the bucket to make a wet slurry, and work the surface of the glass. 3. If the problem is severe, keep dipping the scourer into the powder to make a dryer paste. 4. You will notice the surface become smoother and smoother, then simply rinse off. Works in hard or soft water, and is septic safe. Recommended for use on:  Shower screen glass, Patio and Pool Barrier Glass, Brass, Copper, and Silver, Stainless Steel.