On 09/06/2021 12:54, R D S wrote:
On 09/06/2021 12:04, Muddymike wrote:

You've had a chemical in it that's removed the coating.


It's had nobbut water in it. And an occasional teaspoon of Phostrogen.


modern galvanising seems to be so thin it is just a film on the
metal surface. I replaced the manhole cover behind my house 25
years ago and within 10 years the galvanising has just gone, to
be replaced by rust. If I had known this would happen I would
have paid a bit more for one that was intended for public access
areas (but not vehicle-proof).

Buy cheap and you will buy twice. Drat.