Rasp 3 doesnt' start GUI desktop due to SD full space

Hi,

I have been running tt-rss in my Rasp3 for some months. Suddenly, it stopped working. When I reboot the Rasp, I see that it’s stuck in the black screen asking user/password. After logging and typing

df -h

I see that the 28GB available are full. How can I empty my SD card if I cannot enter into the GUI desktop, please? Which is the TT-RSS entry directory?

2 week probation for ridiculous off-topic