[tatman]

whats the best thing to get water stains off glass. got a customer with an overflow pipe above the window it drips onto and is really badly stained.

[cybersye]

I spray on a solution of ammonia and pure water and then use a scraper with a new blade

[russ_clark]

Mineral Deposit Remover (MDR)
Put in on with a rag -leave for a few mins then wipe it off and buff it up.
sold by www.windowcleaningwarehouse.co.uk for about a fiver will last for ages.
Russ