The only way to remove hard on calcium is to machine buff them using a cutting compound and plenty of water. The only problem is a chance of swirl/scratch marks but will always look better than the thick calcium build up! Metal shine/acid will also get rid of it but will leave streak marks on the glass and paint (if removing from a car).
In order to clean calcium off windows you need to use a heavy solvent. For all natural approach you can use vinegar and sunlight soap and a grey S.O.S. pad if you use green it will scratch your windows. If that does not work you can try C.L.R. which quite effective at removing hard water off of windows again scrub hard with a grey S.O.S. pad. Lastly if it is a very bad window you can use sulfuric acid with an old sponge and gloves. then you scrap off afterwards with a special scraper made for windows so that you do not scratch your windows. I actually just had a professional come in from mike's window cleaning in Ottawa and they did an excellent job at removing the hard water left from my sprinkler system.
You can clean calcium buildup on windows by mixing equal parts water and white vinegar in a spray bottle. Spray the solution on the affected areas, let it sit for a few minutes, and then scrub with a sponge or cloth. Rinse with plain water and dry with a clean towel to leave your windows sparkling clean.
Acid Water
White vinegar will dissolve most water spots and leave glass extremely shiny. Very stubborn marks may be calcium deposits or etches on the surface of the glass. CLR will remove the calcium, and if the scratches are not too severe, rubbing with a paste made of baking soda and water will polish them off.
You can clean calcium deposits off with vinegar. First loosen the deposit as much as possible, then heat white vinegar in the microwave and pour into a spray bottle. Spray and let deposits sit until you can wipe them off.
I use one of those straight razor holders and scrape it off.
To clean calcium from a kettle, mix equal parts of water and vinegar and let it sit in the kettle for a few hours. Then, scrub the inside of the kettle with a brush or sponge to remove the buildup. Rinse the kettle thoroughly before using it again.
Scrape off what u can with a razor blade. White vinegar should remove what's left.
Mixture of 50/50 methylated spirits and water
Try CLR, the calcium, lime and rust remover. It's in most supermarkets with the cleaning supplies.
Both are good, it depends on what type of tile your trying to clean. Tile Savers of Houston.
No, not necessarily. It depends on what you are trying to clean off and what the surface is! Obviously you don't clean windows the same way you clean the sheets on your bed! Different tasks require different measures.
Do not clean windows in the sun. Clean windows with cleaner that has ammonia in it. Also use squeege and wipe streaks with newspaper.