Clearing Cell Contents Daily Automatically

Gm12367 It appears that you have done some experimenting, and have tried code in the Workbook_Open event.  That seems good.  All your workbook needs is knowledge of when (which day) it last performed a clearing action.  That knowledge could be stored in a reserved cell in a reserved worksheet (which is possibly hidden).

Store an initial date value in your special cell.  Then, your Workbook_Open code should include something like:

    If Date > Sheets("SpecialData").Range("B2").Value Then
        '   It's time to do a cleaning.
        '[do the cleaning (either with code here or in a called procedure)]
        '   Record the date of latest cleaning:
        Sheets("SpecialData").Range("B2").Value = Date
    End If