They kept the envelopes?

"We had been working in the house for a month now, and Leslie and I were downstairs in the dusty, musty “Den”. When we first poked around the ground floor assessing the mess, the Shop/Garage, packed full of parts, tools, and junk, had appeared to be the hardest job. Looking at it now, I would have to say this room was worse. It had been filled, to the doorway, with stuff: bookcases; books and manuals; boxes and boxes of electronic components; rolls of fiberglass fabric; boxes of photographs; essentially everything my Dad wanted to keep but didn’t want to have to deal with.
I was currently perched on The Ugliest Couch Ever Made, a hideous mushroom-colored, vinyl decorating statement, which went perfectly with the dingy, matted gold carpeting. Surrounding me were our constant companions, the boxes that had moved with us from room to room, floor to floor; boxes marked Keep, Shred, or Recycle. They had been emptied, of course, many times, and they continued to fulfill their tasks as way stations for every single piece of paper we found.
The Den boxes were filling up quickly with the moldy engineering tomes from Dad’s days at college, important and semi-important papers, and those vital twenty- year-old airplane magazines that were apparently just too valuable to let go. Christian had also finessed (sawn) the lock off the large, green filing cabinet that we had hoped would be filled with plans for a nuclear reactor at the very least. Just to liven up the work a little. We found, to our great disappointment, more useless paperwork, including every credit card statement he had ever received, utility bills, engineering diagrams, and receipts and papers pertaining to the house and rental properties.
In one little lock-box, we did find the receipt for my mother’s diamond engagement ring, as well as some energy bills from 1970. It appeared my parents couldn’t relinquish any scrap of paper that entered their hands. They kept everything, even the junk mail, in the original envelopes."