Those white blotches look like mold. Not much you can do there except to use film restoration software to eliminate those blotches in your digital scans. There is an app called Neat Video that can do some restoration, but I only use it for removing noise from images. (I’ve observed that its dustbusting tools can introduce artifacts into the film that didn’t exist before.)
Another post-production tool that you might consider is HS-Art’s Dustbuster+. It’s a standalone Windows or Mac app that can do automatic/manual dustbusting and manual image repair. But watch for sticker shock. They will sell you a license and dongle for about $1500. They provide support for about 1 year. The tool is good if you have time and patience to clean up images yourself. (DustBuster+ is about the cheapest professional tool I could find for dustbusting film. The next cheapest tool is a few of the Phoenix/DVO tools from Digital Vision at about $10,000. And you need a beefy PC workstation to run them.
As for physically cleaning the film, you can use pads and cleaner. I’m on other forums that have discussed how to clean films from time to time. The top pros recommend an ultrasonic clean by a machine that uses sound waves to shake literally shake the dirt out and off of the film.
A more affordable way is to manually clean the film with chemicals. And here’s where nobody can agree with 100% certainty on what works best. Some people use a chemical called Film Renew. I use VitaFilm. There is a chemical called FilmGuard, which is said to fill in the scratches on a film’s emulsion so that you can transfer it without transferring the scratches. (I haven’t tried that yet personally, but it might work.)
One thing that I would NOT use is isopropyl alcohol. Isopropyl could really dry out a film print.
There are many film cleaners on the market. Those I mentioned above are just a few.
Good luck! -----Todd Ruel
PS: I agree with drcushing. Ya gotta keep the bug!