This week, quite accidentally, I hit upon a great way to get rid of clothing you no longer wear.
Step 1: Don't do laundry for a long time. And I mean a long time. Run yourself down until you are literally scraping the bottom of the barrel (or closet, or dresser drawer) trying to find something to wear.
Step 2: When you feel like you don't have anything else seasonal to wear, go through your clothes. While you feel like you don't have anything to wear, chances are there are actually quite a few things remaining in your closet or drawers.
Step 3: Get rid of anything that's left in your closet, unless there's a good reason why you haven't worn it. Too dressy, not seasonal, etc. Be ruthless! If you still haven't worn it, even with almost nothing left to wear, there's a reason for it. If you won't wear it when you're practically out of clean clothes, are you ever going to wear it?
Step 4: Drive to the thrift store and drop everything off before you change your mind! Most likely you won't miss anything once it's out of your house (especially if you wouldn't wear it even with nothing else available), but the longer you have it there, the more chance you'll change your mind.
And yes, I just did this. I recently went through my clothes, but even so, I found quite a few more T-shirts to get rid of! One step closer to have a cleaner, clutter-free closet.