Despite all the issues of hierarchy and man-made structure within the Roman Catholic Church, one advantage is that they have preserved tradition and practices through the ages. In short, they have methods that are reliable, and it's all written down.

Most protestants are far less disciplined in terms of documenting this kind of stuff, but they still perform exorcisms regularly.

Fun fact- every Catholic church (almost, they have slackers and temporary issues) has holy water available on request, sometimes with a modest charge but usually free. Although Protestant pastors will bless water on occasion, I've never known a Protestant church to make it really available to the public or even to the congregation. Holy water is a very useful tool when fighting or exorcising evil spirits.