How do I clean a vintage 1970s nikkormat slr camera?

Let me start by saying that nobody advises cleaning the mirror. Also a dirty mirror will never show on the film. If you have dirt showing on film then you have a dirty lens. The lens could have dirt inside the lens. I don't recommend trying to disassemble the lens to clean it. Take it in to a camera repair shop. Let me assure you that you can clean the mirror. You must be very careful. If you put to much pressure on the mirror it will break. Get yourself a blower brush if you don't have one. Blow the inside of the camera out with the blower brush, never use compressed air or canned air. Then use the brush very lightly to remove the rest of the dust. If you have a very light touch you can then use lens cleaner and tissue to clean the mirror. Make sure no big particles are on the mirror before using the tissue. The mirror scratches very easy. Don't try to clean the mirror very often, it was not designed or thought to be cleaned. Always keep a lens or body cap on the camera at all times. If you need a manual try this link. http://www.mir.com.my/rb/photography/hardwares/classics/nikkormat/fseries/ft2/

Dirt on the mirror and viewfinder will not show up on the film. Leave it alone, use it as is on Sunday, then take it to a reputable camera repair shop and have them look at it.

In a camera of this age, it is likely that the interior foam is also long past due for replacement, to the point of disintegrating. That may be the source of a lot of the "dirt". I would not advise using canned air. Only use a blower brush inside the mirror box. As stated before, dirty mirror and viewing screens will only affect the image through the finder, not the image on film.

ok this is what you do u need a can of compressed air and if you do not fell comfortable about doing it find a camera shop that will do it for you

Dust on the mirror or viewfinder will not affect the image quality for the vast majority of film cameras. The mirror is lifted out of the optical path when you take a photo, and there are only the lens elements in the optical path. So what is important is that the lens itself is clean, and you can do this safely with a soft brush, suitable soft cloth or lens tissue, and lens cleaning solution. A blower would be handy, because it does not touch the lens surface, but a clean brush would still be okay. You can used canned air, but there are risks. All the advice I have ever seen is NOT to use canned air on the mirror or focussing screen. The major issue I find is getting small amounts of the propellant smearing onto the surface being cleaned. This then has to be cleaned away, and for optical surfaces, you are then no better off than you were when you started. Remember that the mirror has the reflective surface coated on the top surface and it is unprotected from scratching, etc if you try and clean it. If you need to, use a cotton bud or something similar and work very, very carefully with as little pressure as possible. See the link below as well. It is about digital cameras, but other than some specific advice about storage media, the rest of the advice applies to film cameras too.