|Those mentioned files are used when surfing on the internet. Cookies can save information like a password for instance.|
Cookies can be used to track your surfing habits, to help you go back to a previously visited site, etc.
You can set your browser setting to delete cookies when exiting if you wish.
These files can quickly use up lots of hard drive space.
Download and use Ccleaner Slim from the link below to cleanup those files.
Note that it may delete log-in passwords to sites like this one. There are ways to avoid that if desired.