Hi MacPC,
You can see the cookies in Safari's preferences, under the Security tab. Click the button labeled Show Cookies. From there, you can delete any single cookie or all of them.
If you want to clear everything in Safari (cookies, history, bookmarks, etc.) you can select Reset Safari from the Safari menu. This returns everything to it's brand spankin' new (clean) configuration.
As for viruses/malware/adware on the Mac...there aren't any.
Chris