Clear existing data before running another macro?

Hi, I am new to VBA, I currently have a drop down list and when you select a value, the macro that corresponds to that value runs. The point of this is to display a different chart when you select a value. However, when you select a new value, the previous macro that ran doesn't disappear so the charts overlap which is pointless. How can I tell excel that it needs to clear the previous chart/macro before displaying the next? Any help would be appreciated! To be clear all I did for my macro was copy an existing chart and paste it into another sheet. Maybe there is a better way than that? Here is my code:

Option Explicit

Sub DropDown2_Change()
    With ThisWorkbook.Sheets("Dynamic Charts").Shapes("Drop Down 2").ControlFormat
        Select Case .List(.Value)
            Case "1": FirstChart
            Case "2": SecondChart
            Case "3": ThirdChart
            Case "4": FourthChart
            Case "5": FifthChart
            Case "6": SixthChart
            Case "7": SeventhChart
            Case "8": EighthChart
            Case "9": NinthChart
            Case "10": TenChart
            Case "11": ElevenChart
            Case "12": TwelveChart
            Case "13": ThirteenChart
            Case "14": FourteenChart
            Case "15": FifteenChart
            Case "16": SixteenChart
      End Select
    End With
End Sub

Originally Posted by nathansav

set the datasource to be an empty string.

How exactly would I do that :s, I know nothing about programming.

Really need help!