This article covers how to clear the cache created by apt in a completely safe way. It is faster and simpler than manually deleting the cache directory. apt (Advanced Packaging Tool) is the package installation and dependency management tool in Debian and other Debian-based distributions. It works on top of 'Dpkg' which is nothing but the Debian package installer.
The way apt installs packages is: it downloads the package for the required software, and additionally it downloads the packages for all the dependencies for the required software.