Removing Hard Water Spots from Glass

I had some re-heeeally bad water spotting on my boat's plexiglass windshield. Nothing, I mean nothing, would remove it.

My wife had a bottle of Lime-Away in the bathroom. I dilluted it 50/50 with distilled water, soaked a terry cloth rag with it and rang it out good. Wiped the windshield down and "Viola..." the water spots were gone.

Afterwards, I used a plastic polish and the windshield I though I was going to have to replace, looked nearly brand new. Using this on glass would be even easier, could probably use it full strength.