There are several reputable archival material suppliers and most of them offer free catalogs. These catalogs illustrate the product and indicate what they are used for. Certain plastics are used for the storage of negatives and prints. There are m any plastics that are safe to use for photographic preservation. There are many materials that are not safe and should not be kept in close contact with the photograph.
Deterioration can occur from direct contact with some materials or from the fumes they exude.
For proper mounting and identification systems, check with your archival supplies catalog. My mother helped me identify my great-grandmother, my grandfather and all his brothers and sisters. She took a ball point pen and wrote across the only photograph we have of my great-grandmother as a young lady. She did this to all the relatives in the picture. Hopefully, you have now learned enough about photographic preservation to know that you should never wash a photograph, erase it or scratch it.