Calcium Stains On Windscreen / Sunroof

[krwlng]

ey guys

expert advise needed on my issue.
2 weeks ago, i parked my VW Polo in a covered carpark and 11 hours later i came back to find white deposits on my sunroof running down to my windscreen. Checked up and saw looked like stalactites dripping water on the car. I come from a tropical country and i guess it was ground water run off combined with the concrete.

The white buildups were hard and i managed to remove them with vinegar.
But here's the problem.
There's a water stain that i cant remove. i can only see it when the car is wet and the patches/run off are darker than the rest of the glass.

I've tried smooth surface clay kit with the utimate quik detailer but it didnt help. purchased the water spot remover and gave it a good scrubbing and it didnt help as well.

What else can i try?[COLOR=#000000]

[GSKR]

Try clr.calcium lime remover.If you have a home depot near by it should work.Here are the don'ts do not apply on windshield pinstripes or anodized aluminum. Put it on dry rather than wet let set for 2 to 3 minutes rinse.If that doesn't do it contact a professional. Before you try clr wet a Terry cloth and some polish and rub it off with moderate pressure.Before you try to polish it off make sure those areas are clean.The last thing you want to do is rub grit into the paint.On the sunroof there's a product called barkeepers friend its a cleansing powder.Try that on the roof glass with a damp Terry cloth.If you don't or cannot get terrycloth take.a sock turn it inside out.The only true product that will work for is pretty hazardous and I won't.give you that info.

[GSKR]

Heavy compound on paint with machine.Try compounding the glass as well with machine.Or consult parking lot.people and see if there responsible good luck.

[krwlng]

Heavy compound on paint with machine.Try compounding the glass as well with machine.Or consult parking lot.people and see if there responsible good luck.

i unfortunately cant get access to any of those products since i am in singapore.
can i try meguiar's ultimate compound and apply by hand?

[rlmccarty2000]

The Meg's Compound by hand will work. Be very careful and spread the pressure out or you will burn through your clearcoat even by hand. I have done it with Scratch-X. Put the compound on a pad, not a microfiber towel. The pad will help you distribute the polishing weight.

[krwlng]

The Meg's Compound by hand will work. Be very careful and spread the pressure out or you will burn through your clearcoat even by hand. I have done it with Scratch-X. Put the compound on a pad, not a microfiber towel. The pad will help you distribute the polishing weight.

i have scratch-x.
can scratch-x be used with glass?