Bleachbit is an application that can be used to clean “junk” files that are no longer needed on the Linux operating system. BleachBit works by deleting cache, cookies and history on web browsers, deleting temporary files, APT and so on. If on Windows this software is like CCleaner,
well that’s a little explanation about bleachbit,
for installation and how to use it as follows

apt-get install bleachbit

after the install process is complete then open bleachbit in the menu Application>System Tools>Bleachbit(As Root)

checklist the system part to be cleaned (my advice is not to check the autoremove checklist)

then click preview to see how much junk files will be deleted. And click the delete icon to clean the junk files.