Removing Mortar Splashes From Glass

[derrynoose]

Can anyone recommend a product which will safely remove hardened mortar splashes from glass? Thanks.

[ummmm]

I'd try a glass scraper first.

[heathfield]

If it's been there for some time, the mortar will have stained the glass due to acids in the mortar, and these stains will be visible from certain angles. It won't be easy, but you can try to get rid of the stains by finishing off with a metal polish such as Solvol Autosol Chrome Polish. Be careful with scrapers. I once removed dried paint from the glass in a panelled door using a Stanley knife blade, only to find the blade had scratched the glass quite severely.

[gingejbee]

Mortar is not acidic - it is strongly alkaline; and it's this high pH which etches into glass and causes marks after some time.

[Old_Geezer]

Wow. In the school chemistry lab they used to keep glass bottles of acid and alkaline. I know it was a long time ago but I don't recall seeing them gather etchings.

[heathfield]

Right, Ginge, mortar is overall definitely alkaline, but any wetted quartz in the sand, ballast or aggregate in the mix can produce silicic acid over time.