No doubt you have a PC, so I can't help directly.
With a Mac - and especially if you use Firefox - but it's simple with Safari too - there is a menu item that will show you the cookies on your computer.
Here's mine for now on Safari there are 50 of them at the moment.
This is just a little few of them that the screen will show. There's a button to remove them all.
On Firefox you can go to Preferences/Privacy/Show Cookies and you can delete them.
No doubt on a PC all that is available too. It's only a matter of finding it.
Thirdcrank has said on another thread that he get adverts because of links and websites. By deleting cookies it gets rid of all that. I make a point of deleting all my cookies - and browsing history - when I log off. Therefore I have a "clean" computer every day when I switch on.
Mick F. Cornwall