A Word About Safety
"Acid-free" and "Lignin-free" are two terms that you will hear over and over again in the scrapbook world...and there's a good reason why. Acid is used in paper manufacturing to break apart the wood fibers which holds them together. Acid + photo's = deterioration. Acid reacts chemically with paper and other materials so its imperative that all materials used in scrapbooks be acid-free. The adhesive in magnetic albums, for example, is highly acidic, so if you have photographs in magnetic albums, get them out now! That should be your first objective.
A pH level of above 7.0 is considered alkaline or "acid-free". Most acid-free paper has a pH from 7.0 to 9.0.
Lignin-free is an important characteristic as well. Lignin is the bonding element that holds wood fibers together as a tree grows and will turn paper products yellow and brittle. An example of this is old newspapers.
* * * * * * * * * * *
Basically, if I understand correctly, the acid will break down what it is in contact with. The lignin will age and turn yellow.
I've never used it myself but I've heard of a product called Archival Mist that you can spray things with to make them safe for scrapbooks. Like I said though, I've never used it so I can't say one way or another if it truly works.
Isn't there a product you can buy that tests the ph-level? Maybe someone else knows more about it.
Good luck with your project!