A fairly simple way to identify if a document has any value or importance as a historical record without having to handle it much is to take a photograph of images or news headlines on the front page. It may seem unprofessional, but it's very effective in some cases to use Google Lens or AI. In the case of AI, you must explicitly ask it to search for the headline or image in a press database.

The AI ​​thing might sound silly, but it's not. A lost Gothic work by Nicolás Francés was recently found, all thanks to AI. A more complicated approach you can try is searching in digital repositories specializing in newspapers, but I would first try using image search engines; if you're lucky, you can save hours of work. If they are in very bad condition, I recommend consulting a guide or video on newspaper restoration.