The mail carriers are kind of known for that and there's not really a quick fix. I put what I can in my envelope, like cardstock or cardboard and then flatten the item when it comes back. That is another reason I like collecting 4X6s.

BossC1

Right now I use card stock, I two in each envelope to make so it should not bend. But apparently my mail carrier does not care. Is there anything else I can use that would not bring the postage up on each envelope ,but keep its stiffness. If you get my meaning. HELP.