How to clear all blank in the cell for the whole worksheet

[climbp19981]

Sub deleteblank  
    Dim book_sht As Worksheet
    Dim sht_Rng As Range
    Dim i, data_rows
    Set book_sht = Worksheets(1)
    Set sht_Rng = book_sht.UsedRange
    Range("B2").Select
    data_rows = sht_Rng.Rows(sht_Rng.Rows.Count).Row
    For i = 1 To data_rows    
         ActiveCell.Value = Application.WorksheetFunction.Substitute(Trim(ActiveCell.Value), " ", "")
         ActiveCell.Offset(1, 0).Select
    Next
    Set sht_Rng = Nothing
    Set book_sht = Nothing
End Sub

I have the above VBA code that helps to clear one column of cell.
How can I modify it so that the code can help me to look through all column?

[climbp19981]

[Logit]

.

Option Explicit

Sub CleanSht()
    Dim rCell As Range
    Dim rText As Range
    Set rText = Cells.SpecialCells( _
    xlCellTypeConstants, _
    xlTextValues)      
    For Each rCell In rText
        If Trim(rCell.Value) = "" Then
            rCell.ClearContents
        End If
    Next    
    Set rText = Nothing
    Set rCell = Nothing
End Sub