How to do the same thing TextMechanic does in Microsoft word?
The link that you shared is for text based files only. You'll need to be working within Word itself to work with this, but follow some of the instructions from the following link:
Take time to read through it and try the tips that they give, also make sure to make a copy of your original file so that you can go back to where you started.
If you want to get rid of text that matches the searches use the find/replace functionality and use the replace box filled with nothing to remove the text you find.