Trying to convert RTF-formatted text on the clipboard to plain text is a nightmare. There are many solutions out there, some of which cost money, and others which are free but don't work reliably. So here's an AppleScript that will do the job:
Turn it into a run-only AppleScript, bind that AppleScript to a keyboard shorcut with a utility like Keyboard Maestro (my personal favorite), and never look back again. Note that the code above is adapted from the script "clip2pure_text" found at the bottom of this blog post.
try set the clipboard to string of (the clipboard as record) on error errMsg display dialog errMsg end try
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