I want Miss J (2 1/2) to learn how to "declutter" things herself, so before Christmas I told her that since she'd be getting new toys, we better make some room for them. I asked her if we could go through her toys and find some to give to "Baby Luciana" (a 1 year-old friend of ours). We took each bin from the standard toy bin rack, J dumped it out, we went through things either putting it back in the bin or putting in the pile for the baby. I was surprised at how giving she was, and how appropriately she got rid of things — her romance with Elmo is over, so everything Elmo went. (It was harder for *us* to get rid of the teddy bear with a bell inside she loved as a baby but that now "makes too much noise.")
Some key ideas here — giving to someone specific; only going one bin at a time and quitting when it gets boring; and respecting her ideas of what should stay and what should go.
How lucky for Miss J. that Sara's taking the time to teach her these lessons now. I don't think all kids would be as amenable to the toy culling — some seem to be born with hoarders' instincts. But even encouraging kids to give away one toy (or one bag full) gets the point across, especially when done regularly.
If your kid is one of those who can't part with the toys in the Goodwill pile, I've found that creating a holding area for donations — a large plastic bin that gets stored out of sight in the basement — softens the blow. Toys go there for a while, and then to Goodwill. By the time they make it out the door, they're mostly forgotten. Not as worthwhile a lesson as Sara's hack, which not only teaches organization but generosity, but it's another option.