Hi William,

the functionality you are looking for is found in the "manual/advanced" tab in the Duplicates window. There is a toolbar half-way down in that view, with some buttons. The last one is called "Reset" and allows to wipe out all deduplication information - in two different ways and in one single go, so you won't need to spend time operating on a one-by-one basis. Given your purpose, you will want to pick the second option on offer there (wipe all).

This functionality is described in some detail from page 39 of the user manual (in case it helps!).

Once this is done, you should be able to delete the required sources forever. However, please note that if they are particularly large sources, you might get a timeout error when trying to do so. If this happens, please get in touch via email (EPPISupport@ucl.ac.uk): we can perform this last step for you, when/if necessary.

I hope this helps!