Digital BW, The Print

> For large negs consider using a cover sheet so that you have a 
sandwich of
> glass/oil/neg/oil/cover film. The cover film is taped to the glass 
and you
> can then use film wipes on the cover film to work air bubbles out 
to the
> edge of the negative.
> 
> Martin Wesley

Would some cover material like a clear acetate be sufficent as a 
cover film ? How is the negative cleaned after scanning ? Any danger 
to the emulsion of the negative ?
TIA
Andre