How to not copy samples used in the sampler to the projects folder and/or delete unused samples

When I create a sampler-track and put a sample in it the sample automatically is copied to the audio-folder of the project. Is there an option to turn this off?
Aside from that, when I close the project without saving (not even creating a project file) the used samples still remain in the projects folder. There seems to be no window asking me if I want to delete unused samples.
Is there any way to prevent Cubase from copying and/or keeping every single sample used in the sampler in the audio-folder of the project?


Do so in the Pool window, please.

Ok. thx! Although I was hoping to find kind of an automatic way to delete unused samples.