It's a hard one isn't it. I don't share the same ideals (for want of a better word!) but I certainly try to limit the amount of c**p that enters my house but well meaning but clueless people who buy stuff that I can tell is never going to be used.

Can you work into conversations with people about how you've been reading up on "green" toys and kicking yourself for buying things that don't fit in with what you are trying to do - ie make it just lighthearted conversation about what you are trying to do, and hope that they take it in and factor it in next time they buy something?

And then if that doesn't work, maybe gentle requests to the people that regularly buy gifts - I know if I'm buying something for a child I'd much rather spend the money on something that will be used/loved than put away and never used.