Add a clear values code to command button

I am using a command button to autopopulate one worksheet (named ranges) with values from another worksheet. (thanks to this forums help!).

One slight problem. When i change the values in column b on "invoicing" worksheet, which designates which column in "cashflow" worksheet to put the data in, i am left with duplicate values. Data input into the originaly populated column and also the new data.

All i need is a code to add to the command button that will clear all values in worksheet "cashflow", columns C:? first, then run the code required to populate and new information.

For more information, please see my post http://www.excelforum.com/excel-prog...-criteria.html

Please see sample file attached, and note that i have indicated particular ranges on the code that do not show on this attachment, as it is only a sampling of my file.