This is an absolutely free online tool I designed to replace in bulk all the special, strange and dodgy characters from my subtitles. You can use the inbuilt replace-pattern file, or you can simply create one of your own. There is a help section that teaches you how to do it.

What differentiates this replacer from other ones on the net ? Well, you can simply drag your files in, there is no uploading nor downloading involved, you can work not only with characters, but with entire strings, you can work with multiple characters/strings at one time, you can set which characters or strings to just trigger an alert, without being replaced, and, by constructing your own replacement rule file, you don't have to repeatedly enter what you want in the page; just drag and drop your file, and the result is automatically copied in your clipboard.
Now supports drag-and-drop ! Just drag and drop your files into the respective areas, and you're good to go !
It also supports forced utf-8 conversion - for the files that are actually ansii files !
As I said, this tool is absolutely free, no adds, no strings attached. There is nothing to download, and you don't have to upload your files. Just paste the result, overwriting the content of your subtitle file.
It works with all kind of subtitle files, text based files, and even other type of files.
To use it, simply go to the link provided in the "link to the product homepage" and follow the steps

Have fun and hope you'll like it.