Ideas for cleaning white scale from exterior door glass?

I've come across a circa 1965 wood door with four large glass inserts. This is an exterior entry door to a garage and the glass has what appears to be a white-ish scale on the lower exterior sides.
I've tried just about everything I could think of to remove this scale without success including white vinegar solution.
Can anyone please make some recommendations, short of replacing the glass, in an attempt to remove this unsightly scale?
TIA
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bobmct wrote:

1) lacquer thinner (right next to the paint thinner / varsol on the shelf of your local hardware store. Gasoline, toluene, acetone or nitro-methane might work if lacquer thinner fails. The use of these solvents would be advised if the scale is the result of some sort of paint, glue, caulking, sealant, etc.
2) a 50:50 mixture of water and muriatic acid (hydro-chloric acid) soaked into a paper towel and applied by hand (wear gloves if you're thin skinned). Muriatic acid can be bought in gallon- sized jugs at Home Despot and other big-box hardware stores, and probably also pool supply stores (might be called "shock"). Use of acid would be the way to go if the scale is a mineral deposit of some sort.
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bobmct wrote:

Razor blade.
--

dadiOH
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