I have to agree with 1ke. It is very uncomfortable when a clerk asks you to “donate $1 to such and such” (I like to really know who my money is going to…some stores give to questionable charities) and wouldn’t be comfortable with a friend asking me to donate to a specific charity. Although you may feel the cause is a worthy one, not everyone will (example: protestant donating to Catholic apostolate, non-animal lover donating to shelter, a pro-life individual donating to any medical research without knowing their position on stem cell research). People may feel obliged to donate to something they aren’t comfortable with (my favorite charity is so poor that I doubt if they’d have brochures!). Also, it could be construed as self-advertising your own generousity.
If anyone does ask what you’d like, you can give them a brochure.
Good for you on addressing envelopes already…I truly waited until the last possible minute to address and mail my cards!