Thanks, I just did. It is medium-filthy. Any idea to self-CLA it?
No CLA .
If the mirrored surface has oxidised , it will never be as reflective as a new one .
For $7.50 there's no point compromising and struggling. Just fit a new one , I'm replacing all off mine .
No lubrication , and no adjustment ( the other bits if a cLA) the mirror slots in its place behind the lugs that were ground in the factory , and the screen goes back on exactly as it came off .
Only investigate the position if the screen if your shots are out of focus .
It's a DIY job to replace , very simple .
It's not so much the dirt that makes it dull , the coating on the mirror oxidises and reflects less light over time .
Don't forget it's a front surface mirror , so there's no glass to protect it .
The place I always get mine from is off Marty on eBay ;
https://www.ebay.com/itm/264715927181
, Good price and good quality .
When you get it , you'll notice it has a piece of blue plastic on it .
This is to protect the mirrored side and should be removed before installing and faced up .
It's been asked on here before why the new mirror someone has fitted us dull .
It's because they assumed the blue side was the back and the shiny side was the front .
Just something to be aware off .
If your ground glass needs cleaning , I've carefully and gently done mine in water with a bit of washing up liquid in it .
Then rinsed in clean fresh water .
Then given a final rinse in distilled water before standing on edge to dry off .
Remember , some focus screens are duller than others , so yours might not be dirty anyway .
Asses it when you change the mirror .
Me too. It's a delight.