The principal factors contributing to the deterioration of paper are oxidation and acid hydrolysis caused by chemicals it contains. Light-induced oxidation of lignin, the component of the cell walls of plants which is widely present in paper, is what turns newspapers yellow.

Meanwhile, the cellulose fibres are cut by a reaction involving heat and acids, which turns the paper brown and brittle. To prevent these reactions, keep the newspapers cool, dark and dry.

The folders and boxes you keep your newspapers in should be made of acid-free material, to prevent acid migrating into the paper. Interleave newspapers with acid-free paper and encapsulate it with polyester film or Mylar. Don't use ordinary plastic or vinyl because these contain solvents and additives that can migrate into the paper.

There are sprays and solutions available that prevent paper turning brittle and yellowing. The deacidifying solutions Wei T'o, Bookkeeper Archival Mist all contain methoxyl magnesium methyl carbonate. Impregnating paper with these alkaline solutions neutralises existing acids and oxidation.

You might also wish to deacidify old newspaper clippings. A recipe for this is to dissolve a milk of magnesia tablet in 1 litre of soda water and let it stand for eight hours, then pour the mixture into a glass or plastic container. Do not use aluminium pans. Soak the paper clippings in for a hour and hang them out to dry completely. Make sure you test the on the clippings to make sure it won't run, before using this method. should change the solution when it turns yellow."