I am so glad you posted this. I have a bunch of envelopes I just put in the recycling bin. I'll start saving them for you, along with the cards and soda tabs.
Karrieann, I would love to do this too. I will start collecting today when the mail comes. What a fabulous cause, thanks so much for bringing this to my attention. I get a lot of mail so would you please email me your address. Thank you. Hugs, Deb