I recently purchased and needed to service a Minox C, due to battery corrosion from the previous owner. The corrosion was verified to only be on the contacts, so all is well that concern. When I opened the case, however, a small tinted filter fell out from somewhere, but there are multiple places where it fits and could have fallen out from. [small filter is about 2 mm square] Unfortunately there are no detailed diagrams of Minox C internals online, only the B model, which seems to be well illustrated online. The filter fits in the two different tracks where the other filters can slide left or right, but I would doubt it goes here: Does anyone know where this filter goes? It fits nicely in the front, but that would mean it is used full time. (The forum system calling the links to the photos of this filter "spam like", though it is from Flicker, so I cannot post photos of the questionable items) Is this only engaged during certain lighting selections or does it fit in the front permanently? Thanks in advance.