Thanks for the clarification. We do know about expelling the devil, thanks. From your previous statement I thought you meant that you personally were walking around like Buford Pusser in "Walking Tall" casting out the devil in all that you see. I'm certainly glad I was wrong.
You should really read a good book (I can recommend a few) for some clarification on what Catholics really teach and believe. Honestly, you haven't a clue. If I want to know how to fix my electrical wiring, I look at a book written by an electrician, not a plumber.
I read quite a lot. And as regards 'catholic literature', I'm told that nothing I read has any bearing on how you guys do anything unless it's like the catechism... So, you can read plumbing directions from a plumber and electrical directions from an electrician all you want; but, according to catholics here, it really isn't authoritative and is not what the church teaches or believes.
That said, from personal experience combined with documentaries and readings, your church seems to think that waving crosses and saying 'in the name of the father, son and holy ghost go away' has some importance. Waving symbols is of no use, nor is the invocation of non-specific authority. It may look and sound impressive; but, it is of no practical use.