In article <464elh$ctr@barnacle.iol.ie>, ai@iol.ie says...
>I got negatives developed commercially but they came back pretty grubby
>with what looks like traces of chemical smears in certain places.
>I reckon the stains will wash away.
>These negatives are very precious to me so I was wondering how safe it >is to re-wash negatives?

If the negatives have been cut, it would be safest to wash each strip
separately to avoid scratches. If the rewash is done at a moderate temperature, there is unlikely to be harm done to the film unless
wet times are extreme. Clean cotton batting may aid in dislodging
the crud, but be sure to wash away any loose fibers before drying.
Use a wetting agent in distilled water for 1/2 > 1 minute to finish.
Unfortunately, it is very difficult to remove crud (a technical term)
from film once it has dried on the film, alas.
Hope this helps.