When I import new data, I use the MultiMergeGramplet a lot to get rid of duplicate locations.
It is very powerful, and it does its work well when you merge them on title, and these contain the full hierarchy, so that you don’t merge Harlingen, Friesland and Harlingen, TX into one place.
I have also used this for sources, and today I found that it was not a very good idea for that, because when you have several sources with a generic title like email, which only differ by the name of the author, running Automerge will merge all these emails into one, leaving them as if they were all written by the same author. And that’s not what I want, but to be honest, I must add that it does exactly what it says, merge objects with the same name/title.
I will report this to the author ASAP, but thought that it’d be best to put a warning here first.