Place a box near the front door in a closet, etc. Line the box with a garbage bag. When you come across clothes that don't fit or you don't want then place them in the box immediately. This allows your closet to always be cleaned out and you never have the chore of going through it. This works great for kids clothes too!
As you use things in your kitchen or play games with the kids, etc. you will see items that you never use anymore or just don't want...place them in the box immediately. Once you get the hang of doing this, you will find that your closets, etc. have in them only the things you use & want. It's a system that I read about years ago and really works.
Once the box is full, remove the garbage bag, place it in your car immediately so you can take it to your favorite charity when you have time. Place a new garbage bag in the box. You will be surprised how often you have a bag to give away.