Cleaning Glass On A Gas Fire

[thechauffeur]

I have a glass fronted gas fire and the glass has become discoloured and opaque on the inside because of the reaction to the heat of the fire. what product would be best for cleaning the glass and removing this film without scratching it ? Thanks in advance for any solutions.

[tamborine]

WD40

[ivor4781]

when we had a parkray we "gently" used water and a green scrubbing pad