Lin Mu knew that retrieving lost objects from the minor void was a relatively easy task for him. Though for almost all others, it might be an impossible task depending on how long or where the object was lost.
Usually, the destruction of a spatial storage treasure meant that the things kept in it were as good as destroyed, but some could eject the objects into the minor void instead. There were even specialists whose main occupation was to retrieve these objects.
Of course, someone that did this needed to be an expert in not only formations but also have a good affinity for the spatial element. The first requirement was sufficiently easy to fulfill, but someone having an affinity for the spatial element was incredibly difficult.