A practical solvent cleaner design [for example the Comet, in Italy] that avoids the problems of buffers and the excessive contamination of solvent from very dirty archive film uses a cotton band or bandage in a roll wet with solvent that slowly wipes the film surface running in the reverse direction to the film drive. The cotton band is used only once before being discarded. These cleaners are very effective for very dirty film, surprisingly economic but do use more solvent than the reclaimable systems.
The solvent used could be varied but all or most use Perchlorethylene