Most people are forgetting about the large envelope shipping option. It is for stuff that is between 1/4" and 3/4" thick. As far as envelopes not going thru their machine that is why they have a $.15 "non machinable" add on for envelopes. Sometimes you just have to copy their shipping rates and rules and show them to the cage critters to try to get them to understand what THEIR rules really state. Years ago I had an argument with one postal clerk so I spoke to the head postmaster. She didn't have a clue as to what rates should have been and had to pull out her postal rules book to check.