Large Excel file - how to reduce the size?

I have an Excel file with UsedRange = A1:CH102. The saved size is 4151 kB. I have found a way to reduce the size:

Option Base 1

Sub ReduceSize()
  Dim lAntR As Long
  Dim iAntK As Integer
  Dim aR() As Single
  Dim aK() As Single
  Dim n As Integer
  Dim sFil1 As String
  Dim sFil2 As String
  Dim sKat As String
  Dim sArk As String
 
  sFil1 = ActiveWorkbook.Name
  sKat = ActiveWorkbook.Path
  sArk = ActiveSheet.Name
 
  lAntR = Cells.Find(What:="*", SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row
  iAntK = Cells.Find(What:="*", SearchOrder:=xlByColumns, SearchDirection:=xlPrevious).Column
 
  ReDim aR(lAntR)
  ReDim aK(iAntK)
  For n = 1 To lAntR
    aR(n) = Rows(n).RowHeight
  Next n
  For n = 1 To iAntK
    aK(n) = Columns(n).ColumnWidth
  Next n
 
  Application.CutCopyMode = False
  Range(Cells(1, 1), Cells(lAntR, iAntK)).Copy
  Workbooks.Add
  sFil2 = ActiveWorkbook.Name
  ActiveSheet.Name = sArk
  ActiveSheet.Paste
  Application.CutCopyMode = False
 
  For n = 1 To lAntR
    Rows(n).RowHeight = aR(n)
  Next n
  For n = 1 To iAntK
    Columns(n).ColumnWidth = aK(n)
  Next n
 
  Workbooks(sFil1).Close savechanges:=False
  Application.DisplayAlerts = False
  Workbooks(sFil2).SaveAs sKat & "\" & sFil1
  Application.DisplayAlerts = True
End Sub

But still the size is about 1400 kB.
Do anybody know what was occupying space outside the UsedRange?
Do anybody know what kind of format or content or anything else which takes much space? Is there a way to analyse the size of each cell or element in the sheet?