If you actually mean clipboard then you don't - the clipboard is a reserved area of memory maintained by Windows for copying data to / from, ie the Copy, Cut and Paste options in the current active program and is only accessible by the currently active program.
Is the reason you are asking because of this dialog box?
Thank you - using the option to Save to directory option in the dialog ia actually very useful - it allows you to do multiple grabs from the program saving each one as you go along, without having to switch to another program to paste the screen shot into and save it.
Googled to find the best "option to Save to directory option in the dialog" but found none can you please kindly share which method works well for win 7 , please ?