Excel - Make macro work for multiple files?

[Fizziii]

I have the following code that I would like to change. I initially wrote this to work with a specific couple of files, and I'm finding that I need to have it be able to work for multiple files for both the dnc/ccl lists. I've never been good at code that allows you to select files from an open dialog. Can someone help me with this, either with sample code for selecting files, or by tweaking the below?

Sub Cleanup()
Dim sTmpEmail As String 'Email address we're checking
Dim iDNClist As Integer 'Loop counter for Do Not Call List
Dim iCustList As Integer 'Loop coutner for ColoradoCustomers spreadsheet
Dim dnc As Worksheet 'Do Not Call worksheet
Dim ccl As Worksheet 'Customer list worksheet
Set dnc = Workbooks("DoNotMailBook.xlsm").Worksheets("DoNotMailSheet")
Set ccl = Workbooks("Customer ListBook.xlsx").Worksheets("CustomerListSheet")
Dim dncS As Range 'Do Not Call Cell A1
Dim cclS As Range 'Customer List cell A1
Set dncS = Workbooks("DoNotMailBook.xlsm").Worksheets("DoNotMailSheet").Range("A1")
Set cclS = Workbooks("Customer ListBook.xlsx").Worksheets("CustomerListSheet").Range("A1")
Dim dncC As Integer 'Do Not Call last row
Dim cclC As Integer 'Customer List last row

dncC = dnc.Range("A65536").End(xlUp).Row
cclC = ccl.Range("A65536").End(xlUp).Row
Debug.Print dncC
Debug.Print cclC

'dnc.Range("A1").Font.Bold = False
'ccl.Range("A1").Font.Bold = False

Application.ScreenUpdating = False
For iDNClist = 1 To dncC
    sTmpEmail = dncS.Offset(iDNClist, 0).Value
    For iCustList = 1 To cclC
        If sTmpEmail = cclS.Offset(iCustList, 0).Value Then
            cclS.Offset(iCustList, 0).EntireRow.Delete
            cclC = cclC - 1
        Else
        End If
    Next iCustList
Next iDNClist
Application.ScreenUpdating = True

End Sub