What's the best tool/method to clean a mirror and focusing screen?

What is the best tool and method to use to clean the mirror and focusing screen? Thanks for the inputs

Rocket blower. I'd never attempt to clean a mirror with anything that involves physical contact, too much chance of getting things misaligned. If the focus screen is removable then you could take it out and clean it carefully. But I'd leave it - it's not going to affect anything important.

There is nothing that will clean a mirror without the danger of scratching it. If it's really dirty, send it to Canon before trying to clean it. Cause if you try and clean it, you'll have to send it to them anyway.

Mirror can be cleaned with a blower, staticly charged brush, sometimes I use a sensor swab with Visible dust sensor clear solution and a very light touch.

Focusing screen is really blower only, once you remove it from the camera, to blow on it inside the camera is just asking for more dust to be pushed further inside the pentaprism, causing a bigger cleaning headache.

The fresnel design of the focusing screen gets stained easily by the impurities in water and other cleaning solutions, however sensor clear solution works quite well as it's very pure and evaporates cleanly. The main issue with the focusing screen is that it is extremely fragile and scratches so easily, even a soft micro fibre cloth will damage it.

You can blow off the focusing screen with a bulb blower, holding it only by the tab. Touching the focusing screen with anything, particularly your fingers will damage. The focusing screen is very sensitive, and though it may look like it can be brushed or washed off, doing so will affect system metering among other things.

I have used an FF sensor swab and sensor cleaner to clean the mirror after blowing off anything that would move on the mirror and in the mirror box, mainly because of lubricant droplets on the mirror, but I don't recommend anyone doing it unless they are equipped and know what they are doing.

In any case, dust on the mirror is not in focus, so you won't see it through the viewfinder. Dust, hairs, flakes or whatever that you do see are usually on the underside of the focusing screen and may be blown off or gently drawn off with a charged sensor brush.

Hi Iannes, you were a little faster that me.

John_T wrote in post #10604604
Hi Iannes, you were a little faster that me.

Good to have back up and confirmation