Paperbacks from the 1960s and '70s are other good examples of the deterioration problem. The minimum pH is 7.3. Such papers will not remain acid-free. Books published on permanent paper may have that information printed on the title page verso, or display the lazy-eight symbol for eternity. Most recycled papers do not qualify as permanent papers.
Some recycled paper is made from wood byproducts, some is made from reused paper.
Any paper can be made more durable by the addition of a buffering agent, to stave off acid attack. However, the process of preparing recycled pulp shortens the fibers in paper, which is a key part of its strength. Whitening of recycled paper can leave residues that become acidic, and the commonly used bleaching processes cause the formation of dioxin, which is highly toxic and permeates the environment. Just remember that it won't last long. It doesn't matter, as long as what's on the paper is something you don't want to keep.