Although this 1928 « Chambre du Commerce » coin looks pretty sweet under the light dirt that covers it, it’s not what it seems to be. It’s made of bronze aluminium, an alloy that usually is resistant. However with this paritcular coin, green concretion is visible on the edge which is not a good sign. Of course we could have cleaned it using glass fiber pen but in any case, removing those green concretions would have left the coin damaged (with holes). Since it’s a very common coin, let’s try to clean it with Pararestor. We leave each side 5 minutes in the plastic box provided with pararestor. This product will weaken the crust and clean the coin. Since this alloy is not famous for its patina even after 90 years in the soil, we decided to make a test. Both side look similar when their Pararestor bath is over. On the first side where BON POUR 50 CENTIMES is visible we used the brass tip of the precision pencil to make it « shine » removing as much oxydation as we could; as we had feared the green corosion just left dark crust and holes that cannot be removed. On the other side, we just used a needle to remove the green concretions with accuracy avoiding to make it shine. The difference is obvious…What would you prefer the shiny or the rather untouched matt side ? Our heart goes to the matt one 🙂
