Verdigris can be a problem on daggers (SA,SS, etc.) where the blades rest on the internal runners.When the runners are made of copper alloys it can develop. Verdigris can develop on copper, brass, or bronze when exposed to air or seawater over time. It is usually a basic copper carbonate, but near the sea it will be a basic copper chloride. I believe the copper chloride version is the more corrosive but both are bad. Bronze disease occurs when chlorides come in contact with copper,brass, or bronze. It is irreversible and nearly inexorable. If not treated it can cause the complete destruction of affected artifact and it can spread to other artifacts. The acid content in leather where in contact with copper alloys can cause it, as will human sweat. Always wipe those finger prints off or wear gloves. Clean your artifacts and get some wax on them to seal out any future contact with water, oxygen or chlorides.