Because your browser sends the cookie contents only to the Web server that created them, cookies are a very secure way of maintaining data. Other Web sites have no way of getting cookie information originating from another site.
Cookies can be temporary or permanent.
However, manually deleting them is safe and will not cause problems. I recommend you leave them alone and allow the use of cookies. It isn't possible to do this in Windows 95 without elaborate measures. You may want to consider running ScanDisk at boot up by placing a shortcut in the start-up group. Right-click an area within this folder and select New, Shortcut.