I have bean cleaning some ingrained dirt and old rust staining off my Rowntrees factory sign and have used Astonish oven and cookware cleaner, as recommended by Banjo Boy some time ago. It works a treat, without damaging the enamel - thanks for the tip Banjo Boy!

Glad it worked for you Rich..all the best Spence..

Dont rub too hard and try an area first. It can take gloss off.

Good advice - I will remember that Al!

Are you going to Elsecar Spence - its about time we met up after all these years!

I know mate..wouldnt mind to be honest..Arl let you know if i do..

Thanks for the tip Steve, I mainly used it on the white sky of the factory image and the lettering avoiding the factory itself where the staining was fortunately limited.

Any ideas on how to put the gloss back into an email sign?

Rich,,a permenant marker pen is a good way..dont think there is away of putting the gloss back on..

Carnuba wax. I've had hit and miss results, some signs it really helps and others not as much.