Laminating is a good way to preserve the sheet but here is a little known fact that you should be aware of BEFORE you do it. Many sheets have grease pencil writing on them that sometimes covers codes and makes them hard or impossible to read. The grease pencils had graphite in it which is the same thing used in a regular old pencil. After 40 years the grease is long gone but the graphite remains. You can usually use just a regular pencil eraser to remove it and likely read the code under it. If it does not work your have lost nothing. I have had great results with it on old sheets in the past.