uncluttering one day and one thing at a time

It's a difficult thing to decide when sentimentality is involved. Do you have other things that bring back the good memories of your grandmother? If so, perhaps these sweaters could find a new home. If not, perhaps you could pick a favorite to keep purely for the sentiment. I get the feeling that you wouldn't want to wear them now, perhaps that's also your own way of telling yourself you don't need to keep them forever.