In many old photograph or stamp albums, the pages were made of highly acidic black construction paper or dark card stock. The scrapbook's pages may now be ragged and stained with glue. Modern scrapbookers know to avoid magnetic albums - the type with sticky pages covered with plastic. But they've been around for thirty years, so there is likely to be one in your family. By now, the contact adhesive will have discolored the images.
Contents can also be a problem.
Highly acidic papers, like newspaper clippings, can threaten other mementoes. Pressed flowers not only soil paper, but also they are a temptation to insects. Paper clips and staples can cause rips and rust stains. Avoid exposure to extremes in temperature and relative humidity, sunlight and dirt. Inspect them regularly for signs of mold or pests.