How to completely uninstall Guix in Debian

I installed Guix from the Debian main repository (sudo apt-get install guix). I want to uninstall it, so I ran sudo apt-get purge guix and sudo apt-get autoremove. However, it seems that Guix is still using up lots of space on my computer (e.g. /gnu/store/ and /var/guix/ are still full of files). How do I completely remove Guix?