The Code below works to clean non-printing chars on the activesheet.
DR - 4GUnwired.com

'Macro to Clean special characters out of Excel Spreadsheets
Option Explicit

Public Sub CleanBeforeExportToText()
Dim NumRows As Long
Dim NumCols As Long
Dim i As Long
Dim j As Long
Dim strCell As String
Dim c As Range

ActiveSheet.Cells.SpecialCells(xlCellTypeLastCell) .Activate
NumRows = ActiveCell.Row
NumCols = ActiveCell.Column

For i = 1 To NumCols
For j = 1 To NumRows
'Cells(j, i).Activate 'Comment this out for speed
Set c = Cells(j, i)
strCell = Cells(j, i).Value
c.Value = Application.WorksheetFunction.Clean(strCell)
Next
Next

End Sub