I found that there are a great many scanned 2600 game manuals on the Internet Archive (www.archive.org). I searched for "atari 2600 manual". Some are good scans and some aren't. Downloading is free.
When you click on the items in the list (cover art), the information can be downloaded in a number of file formats (PDF, EPUB, KINDLE, etc.) so that it is easy to make a library of manuals for your preferred reader.
These made figuring out how to play the games a lot easier, at least for the original 2600 cartridge games, both the Atari originals as well as the third party ones (Activision, etc.). I printed the ones I was interested in on 4x6" paper then spiral bound them into a book so I could take it with me for reference while traveling.