Well, apart from the good suggestions of the use of archival transparent sleeves, you may find this entertaining to watch

:
Murder on the screen
Especially the last note:
"Every time you handle film, better figure it is is a matter of life and death, because it is. Get a little careless, and we maybe after you for the murder on the screen".
Although it is about cine film, it still has some limited value for handling still film, although I have not heard of people "lubricating" their still film
Marco
Marco,
That old movie is a classic! Just about everything in it is as true today as it was when the film was made.
One small point, though. It refers mainly to 16mm prints intended for projection on TV. Most of what they talk about applies to theater projection as much as it applies to television broadcast but you have to filter for the difference.
The wax lubricant they refer to is probably paraffin or some synthetic wax dissolved in trichloroethane. That was a common lubricant before trichloroethane was banned.
I wouldn't use anything like that on still film. Not because it might damage the film. It will leave a visible residue on the film. In movie projection that kind of thing will not be seen but, in still projection, it will stick out like a sore thumb.
Although common sense tells us that motion picture projection is just a series of discrete events in rapid sequence, the film is always in constant motion, even when it is supposed to be still in the projection gate. As the shutter opens, the light hits the film which causes it to flex as it is rapidly heated. Thus, a motion picture is a very dynamic process with the film constantly fluttering in and out of focus. It is the brain's ability to filter out all that "chaff" which helps create the illusion of motion.
Long story short... The eye/brain does not see any streaking or mottling of the image in motion picture projection while it would be very noticeable in still photography.
I am in the camp of "keep your film clean in the first place and you won't have to clean it so much."
Yes, there is value in using film cleaners like PEC-12 or other things. I keep some of them on hand in my projection booth and in my darkroom but they are something to be used to clean film after an accident or if I have an extra special photograph that needs to be "just perfect."
However, I still believe that handling film carefully is the first line of defense.