Data marked as "garbage", Data store garbage collection

Hi

When I create packages it's going to use some of the disk space. When i delete those packages the disk space is still used. 

I was able to track the location of those used memory localy to this path: C:\workarea\aem-local\author\crx-quickstart\repository\datastore

Deleted it like this:

On this page Data Store Garbage Collection | Adobe Experience Manager, it says that the data store garbage collection should free this used Disk Space from the already deleted package. 

I did run it:

But I still didn't got the disk space back.

My Question:

How can I delete packages so it really does remove the data and get those used disk space back ?

When is data and which data is marked as "garbage" so that the data story garbage collection deletes it ? 

Is there a way to delete something manually ?