My house is over flowing with boys clothes.....HELP :)?

I have no idea where to start??? I have 2 boys, both of their dressers and closets are full plus I have about 5 baskets of clothing. My brother dropped off a bag this week, my MIL dropped off 3. Some fit, some are outgrown by 1 but still to big for the other, some just don't fit either. Some are winter and some are summer, how can I organize this mess?? I am feeling very overwhelmed :(