The back of the film, the side without the emulsion, can be cleaned with a simple film-clean liquid that one can find in specialised shops, such as Tetenal Graphic Arts Filmcleaner, or as an emergency with some denaturated alcohol.

The side with the emulsion is better left alone and cleaned only with compressed air if possible. Compressed air should come either from the manual pump that normally are sold with a brush to clean front lenses, or from some specific photographic can. Don't use generic canned air as that might "spit" extraneous substances to the emulsion.

Complicated cases on the emulsion side should be cleaned with PEC-12, a liquid, in conjunction with a suitable non-lint cloth such as the PEC-pads from the same producer.

These considerations apply, I do believe, identically for enlarging and scanning. A clean negative is a clean negative.