I don't have Microsoft Word, but most applications allow pasting just text using the shortcut Ctrl+Shift+V.

Edit: I see Microsoft Word doesn't natively have that shortcut, but there are two ways to "implement" it here: https://superuser.com/questions/988527/how-can-i-use-ctrl-sh...

Removing rich text formats is a good idea for a clipboard manager feature/plugin, though.