Hi Tiro,
It is very difficult to delete sources at the moment, this is kind of deliberate on our part because sources are the foundation of all information on wikirate and a malicious user could cause trouble by deleting some sources which many metric values are based on.
We can discuss further if you have a specific instance, which you are concerned about, though.
--Vishal Kapadia.....2016-02-04 14:05:48 UTC