Your computer and the installed programs are saving reusable data
in a cache file (temporary memory) on the harddisk, in order to
approach it in an efficient way. After a while it is possible that
the data get compromised and a program starts working in an
unexpected way. Cleaning the cache will solve this problem.
CacheCleaner, as the name already suggest, cleans the cache(s) of
the program(s) you choose. CacheCleaner will let you know, when
it's time to close running app(s) manually which you've chosen to
clean. For security reasons, CacheCleaner is not allowed to close
the app(s) for you.