Are you sure, or unsure??I'm sure what the deposits are, unlikely to be limescale because the water in the Hebrides is very, very soft.
I'm thinking of mild citric acid because that's what I have. Any other suggestions?
I did the same thing, squirted a liberal amount of it on the taps, when I went back some hours later I had a black tap!Of the proprietary products out there, I've used one that stripped the chrome plating off the tap I was treating, so beware. Luckily, the affected area was mostly out of sight. The label did mention avoiding metals, but who reads the small print. I think it might have been Viakal, which doesn't list chrome on our current bottle of the stuff, but it does list gold, silver, copper, and aluminium, as materials to avoid contact with.