You don't have to keep things that once interested you but no longer do.
Do you have a collection that is no longer important to you or no longer a part of how you identify yourself?
Box up the items. If you’re uncertain about donating them right now, move the boxes out of the way for a few months. Do you feel okay not “owning” this collection? Would you be fine with keeping a token number of items from the collection? Notice if you appreciate the clearer space(s).
In a few months, when you realize that you can release the items, pass them along to a current collector or sell or donate the items.