How can I clean the inside of my Rover 25's windscreen?

I have a Rover 25 and find that the inside of the windscreen gets very greasy, or what appears to be grease, and it is almost impossible to clean. It this a common factor or can you recommend a cleaning agent that will safely remove it?

Asked on 16 February 2013 by SW, Bedford

Answered by Honest John
That might indicate a leak in the heater matrix because condensation from engine coolant will appear to be greasy. Fix the heater, and then Mer windscreen cleaner or toothpaste should remove the grease.
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