The tendency for water spots to appear (calcium carbonate deposits), will depend a lot on where you live and your relative hardness or softness of water supply. But after washing negs in cold tap water, I dunk the spiral containing negs in deionised water for about 30 seconds (twizzle about) and then hang them to dry. I never get water spots. However, if you do, all you need to do after cutting them into strips when dry, is put them emulsion side down on something clean like a negative page (shiny side up) and breath on them like you are misting up a mirror and then wipe the shiny side with a soft lens cloth (drying marks only form on the shiny side of the film) and this should get rid of them. If they are still there, dab a little ethanol on the soft cloth and wipe them again. This should get rid of any drying marks (water spots).