If you mean the Smart Tags (tiny clipboard icon beside the cell):
1. Choose Tools>Options
2. Select the Edit tab
3. Remove the check marks from 'Show Paste Options buttons' and
'Show Insert Options buttons'.
4. Click OK
If you mean the Office Clipboard taskbar, choose Edit>Office Clipboard,
to display the Office Clipboard in the Task Pane. There, you can choose
settings from the Options dropdown list.