Removing old packages

I would like to ask you what happens with old packages after they’ve been automatically updated? I just noticed that my root partition space shrunk very much lately.
Thank you in advance

Do you mean, what happens with packages after they are installed?
=> I think they are deleted, but i don’t know that exactly.

I’ve just checked my zypper-cache-folder /var/cache/zypp/.
It’s 36,6 MB, how big is yours?

You can tidy up /tmp, if it has become very big.

My /var/cache/zypp folder is 47MB, I’m asking about updated packages after autoupdate that downloaded new versions and new dependencies. For instance, I had the Linux kernel 2.6.25 and now I have Linux kernel 2.6.27 installed but I see references and folders that contain 2.6.25. I installed kernel-sources and now I see sources for both kernels, I assume they are not deleted. Same goes for libraries and other applications.
How can I remove the old things?

I always wondered the same thing. I have also noticed that even after a uninstall with yast some files are left behind.