Access question

Probably a simple question for someone:
Say you have an Access database (2000 – 03) with one table T1 and a form F1 which displays all of the data in T1 and is editable. Say T1 has a field that is of type check box. How can I put a command button on F1 that will clear the check boxes for all the records? Please keep the answer simple – am fairly new at this Access stuff. – Thanks!!!