Cleaning And Protecting Bronze 1D, 1/2D, 1/4D Etc.

[Gary1000]

A contentious subject I know. Is there a safe way to remove any grime from a bronze coin without taking anything away apart from any surface dirt. Is a bit of liquid soap and water going to leave any long term effects and once clean is there a way to protect the coin.

The problem I have is that all my originally BU coins are toning in my mahogany cabinet. The original red is going fast. Would the hint of say patroleum jelly be inert enough or perhaps a silicon grease. Perhaps I could just do what the victorians did and lacquer the lot.

[davidrj]

Museums use Renaissance Wax on ancients

Dunno whether anyone has done controlled trials on modern BU bronze

Some discussion here

[Peter]

BU copper/bronze seems to be a haven for carbon spots.As a young lad I bought a lot of BU coins from coin monthly.Most of these have toned to red/brown.I haven't a problem with this and thankfully no carbon spots.

Anything with verdigris tends to go out of my collection (apart from a1864 copper 1/4d )

[Peckris]

A contentious subject I know. Is there a safe way to remove any grime from a bronze coin without taking anything away apart from any surface dirt. Is a bit of liquid soap and water going to leave any long term effects and once clean is there a way to protect the coin.

The problem I have is that all my originally BU coins are toning in my mahogany cabinet. The original red is going fast. Would the hint of say patroleum jelly be inert enough or perhaps a silicon grease. Perhaps I could just do what the victorians did and lacquer the lot.

You can't use soap and water on bronze - it would be like water off a duck's back. You could try surgical spirit with a microfibre cloth, but don't rub hard.

As for lustre in a cabinet, you could try a very thin film of olive oil, renewing at regular intervals. The main problem there is the red felt inserts, which would leave traces of red fibre sticking to the coin. But do remember that lustre is a property of the surface of the planchet, and never really goes if it's not worn away. It's still there but can 'fade' or 'darken'. I'm told the original underlying brightness can be restored, but I'm not sure how, nor would be too confident of applying to my own coins.