I decided that I needed to preserve the 2 x Stalpatrone because as you can see in the first pictures there are many spots of rust showing through the ‘blueing’ . Twenty years ago on advice from one of the best Imperial War Museums restorers I started using a conservation liquid called BIOX. This removes rust, tarnish and verdigris, but has no effect on existing paintwork or other markings. As it says on the bottle it is ‘A biological corrosion remover which is completely harmless to man containing no strong acids or alkalis. Designed for the treatment of iron, steel, copper, brass and aluminum’ . I have used it successfully on many items over the years with nothing but good results. I placed the two Stalpatrone in a bath of BIOX and left them to soak for about 30 minutes. On my return I was horrified to discover that the ‘blueing’, if that is what it was, had simply vanished leaving the steel and the rust spots. As it was too late to salvage the rounds in the condition they went into the BIOX I left them until the rust had also been removed.
A lesson indeed as I normally try and preserve any specimens I have in the condition I receive them.
I attach a picture to show the rounds now.