To quickly clear the text/image contents from the clipboard, simply select a file in the Desktop and press CTRL+C. The existing clipboard contents will now be replaced by the file name on which you issued the CTRL+C.
Another method is using Windows Scripting. You can create an instance of InternetExplorer.Application object and then manipulate the clipboard.
Copy the following lines to Notepad, and save as ClearClipBoard.VBS. Double-clicking the ClearClipBoard.VBS clears the contents of the clipboard.
objIE.document.parentwindow.clipboardData.SetData "text", ""