Andy Dingley coughed up some electrons that declared:

On 21 Jan, 00:21, Tim S wrote:

When you don't have any "Silver Dip" to hand, ali foil, boiling water,
salt and baking soda do work a treat on silver (plated) items.

They're also highly damaging long-term. This electro-polishing hack is
an abomination.

Silver Dip (thiourea inhibited with citric acid) has the great
advantage of not being damaging to silver, even when you're cleaning
considerable sulphide tarnish off it. OTOH, it's toxic. Sainsburys
sell it, but not Tesco.

Most interesting - one for the archive