then maybe giving her a box with a lid (that must be pruned when too full to hold more) might be your magic bullet? that way, she gets full control, you don't have to think about it anymore and there's a physical limit to how much hangs around? if she stuggles to make choices when the time comes, you can gently help her through by suggesting she sort things into piles of must-keeps, nice-to-haves and why-did-this-thing-ever-matter-to-mes...
also - it might be productive to chat with her teachers about this issue. they might be wiling to positively reinforce any choice-making she does at school? they might even help her do a pre-sort at school - develop criteria for what's valuable to her (not them! or you!) that might make all of it less overwhelming and reduce the amount she even brings home?
good luck!!
