Hey Tony,
I don't think there's anything wrong with most of the boxes that the factory provides for collectors like us. You have to figure that the old tapes have been in those boxes for 3-5 decades so the boxes are pretty balanced with the pH of the air by now.
Acetate tapes in particular will have some degree of vinegar syndrome so those boxes are higher in acid but actually slow the "gassing out" of those old tapes.
Of course if the boxes have had water or suspected damage for something like oils or chemicals, it's a good idea to get the tapes out of those. The collectors convention is to keep the box and put the reel in a new acid free box.
I have a number of old tapes that I have yet to do anything with. Some are on 10.5" reels but most are pancakes. One of these days I'll sort through them and I'm sure I'll end up buying some new boxes for some.
I do like the old boxes/graphics so I'll try and save as many as I can.
Any that seem torn to the point that their ability to protect the tape when stuffed into a shelf is questionable, or when they have an odd odor or any spec of mildew or unknown staining will get replaced.
Hope that helps
