Youtuber filmismorefun has stated, in his viewfinder cleaning video, that the large diagonal piece of glass in the viewfinder has a special coating and should not be touched. I cleaned this like the rest of the glass and thankfully viewfinder seems totally fine. However, had I known this beforehand, I probably would have avoided cleaning that piece. Here is a link to his video https://www.youtube.com/watch?v=FL3Pkn_ptYs

take your time, dont rush

I was cleaning the flat side of the glass with the round face.  Touched the black mask with the hole in the middle. It fell off. I have no idea how to reattach and center it.

I cleaned my yashica Lyxx 14 finder, the yellow coated semi translucent mirrored 45 degree glass lost its coating so the range finder is useless as there is no yellow patch.  It was very dim to begin with but i kinda finshed it off :-(. I only used some Zeiss Lens cleaner.
I  look in an old canonet 28 to see if I could swap the  coated semi translucent mirror  but its about 3mm shorter in the Canon.  
So i wouldn't touch the coated glass (45 degree glass) maybe give it a brush with a flat sable brush and thats it.

Hi, I have a yashica Electro 35 Gsn impeccable state, but I need a cleaning and an arrangement in the obturado. You fix this type of camera? Could you help me with this?
Thanks for your time.

Thank you for sharing this knowledge on your channel.

Does cleaning the diagonal glasses not misalign them?

Hi, i have Yashica Electro 35. Is there a way ti disamble the lens?

hello could you please let us know where to buy foams kit for light seals and pad ? ebay ? which seller please ? thanks for help .