When you delete a widget, it is removed from your account completely.
To delete a widget, click the Manage Tab, scroll down to the Widget section, and select the widget with a single click (Note: Do not click the Get Code link). Then, click the Delete button located in the small information window (in the upper-right corner).
If the widget is already disabled, you are prompted to confirm your deletion by clicking the Delete button.
If the widget is still enabled, you are presented with a screen warning you that the widget is still enabled and can be signed by signers.
Additional information on Disabling Widgets.
If you do not disable the widget before deleting it, people can still access and sign that widget.