A closet always hides stuff that are not currently in use: old sweaters, faded jeans, scarves fallen behind the stacks. They manage to live through ages in a still state, because sometimes you don’t even recall having bought them at all.
Sort out your clothes from last seasons
Before you get lost in the sorting process be prepared: make room on the table, put the bin next to you (there is always a used handkerchief, a fallen price tag, or a ruined hanger in the closet). Then grab a spray duster and paper towels to clean the shelves!
And don’t put your clothes you don’t need into the garbage. They could make someone very happy. Donate them to charity, to someone who really is in need.