Without manually clearing those fields, a macro is required.

Does this help?

Paste code in a Normal module
  • Where to paste code
  • Highlight macro to copy >> Ctrl + C >> Open your workbook
  • Alt + F11 >> opens the Visual Basic Editor (VBE)
  • Ctrl + R >>opens the Project Explorer (if not already open on left side of screen)
  • Insert menu >> Module or Alt + I, M >> activates the Insert menu and inserts a Standard Module
  • Paste code >> Ctrl + V (right side of screen)
  • Alt + Q >> exits VBE and returns to Excel
  • Back in Excel >> Alt + F8 >> Macro Dialog Box >> Highlight macro >> Run

Sub TrimALL()
   'David McRitchie 2000-07-03 mod 2000-08-16 2005-09-29 join.htm
   '-- http://www.mvps.org/dmcritchie/excel/join.htm#trimall 
   ' - Optionally reenable improperly terminated Change Event macros
      Application.DisplayAlerts = True
      Application.EnableEvents = True   'should be part of Change Event macro
   If Application.Calculation = xlCalculationManual Then
      MsgBox "Calculation was OFF will be turned ON upon completion"
   End If  
   Application.ScreenUpdating = False
   Application.Calculation = xlCalculationManual
   Dim cell As Range
   'Also Treat CHR 0160, as a space (CHR 032)
   Selection.Replace What:=Chr(160), Replacement:=Chr(32), _
     LookAt:=xlPart, SearchOrder:=xlByRows, MatchCase:=False
   'Trim in Excel removes extra internal spaces, VBA does not
   On Error Resume Next   'in case no text cells in selection
   For Each cell In Intersect(Selection, _
      Selection.SpecialCells(xlConstants, xlTextValues))
     cell.Value = Application.Trim(cell.Value)
   Next cell
   On Error GoTo 0
   Application.Calculation = xlCalculationAutomatic
   Application.ScreenUpdating = True
End Sub
If this does not help, would you like to post the workbook and what you want to achieve?