Uyuni Space Problem

Hi Experts
/var/spacewalk/Packages/NULL is taking up a lot of space. Although I only have one system connected.
Unfortunately I cannot see which packages are installed under /var/spacewalk/Packages/NULL. This folder contains subfolders such as : 322 756 370 68h …

How can that be ? Can I delete something here?

/var/spacewalk/suse/media.1 contains the version that I no longer need or that I never needed.
How can I clean this up?

Thanks very much
Best regards