this will be hard, but have you tried seriously just THROWING THINGS AWAY?
Yeah, I'm hardcore like that. If it's sitting out, it goes in the donation bag. PERIOD! Initially, you may end up losing a few things of your ownthat may have gotten lost in all... that clutter. Don't worry, you won't suffer too much. But what i've learned is that standing over a table trying to
figure out what goes where, what to keep or not...is a pain in the A! So don't do it. Just with one arm...SWOOP them all into a bag! :) Trust me, 99% of the time when it's gone, you don't even miss it. We always fear that we may need something for later. Especially, if you haven't used it in 6 months, likely it's not going to have a big impact when it's gone.
So with me before, I literally go through my house every week and start throwing everything into a bag that's sitting on top of a table. Sometimes i sift through it to make sure there isn't a bill...but usually we always keep our bills separate. That was a few years ago...so our house is pretty clutter free. I donate toys all the time.
I'm constantly clearing this house of clutter. We really don't need to keep every paper, items, toys, mail etc...Gosh..the things that are just laying around taking up space. They build fast! But now, as soon as I get mail, I'm already dumping advertisements and opening up mails instantly to throw anything away then and there and file the bills. I don't wait.
So anyhow, it always freaks my husband out 'cause he's afraid I might end up throwing away something meaningful to him...like his comic collections. LOL. He learned fast to put them back where they belong. I believe that your kids will soon learn that if they want to keep anything, they better put it back in it's place, or out they go! Some other kids you're donating these things to will appreciate it. You're still doing a good deed. :)
My kids are only 4 and 1.5, and I constantly recycle their toys, donate etc. If I know my kids haven't played with it in 6 months, it's out. We don't buy new toys unless where getting rid of some.
good luck with this.