Yesterday I found a small metal tin which had some contents. I knew from its shape and size that it was a Maskenbrille box. Maskenbrille were glasses to wear with the gasmask. The box is of very thin metal so most times these are far gone when you find one, or whats left of one. And if you find one intact they often turn into dry rust crumbles when you try open it.
I decided to open the tin. With some antique dentist tool, a light hand and a little patience I managed to get the lid open with only minor damages. The maskenbrille was in surprisingly good condition so I am very happy with this find :)