Thank you! I will try that with single files before trying more of them at once
I'm also open to learning how to use regex for this; I admit seeing the changes as they happen also sound very appealing to me. I read the stickies on using the search & replace function and the intro to regex, but it's still a bit over my head for me.
I did try loading a few of the .txt files to my tablet, and I noticed some of them also have a random character (a question mark in a diamond) instead of quote marks and apostrophes, so I need to figure out how to fix that too. Some of the files are corrupt beyond help - those I will either have to find and redownload, or give up on as a lot of the original sites are long gone.