Remove lots of values from a large Excel without the undo memory overhead

in this case get rid of the null, this was a sparse query output!

Sub RemoveNulls_memoryCheap()
' RemoveNulls_memoryCheap Macro
For cci = 1 To 255
If Not Cells(1, cci) = "" Then
    columnCOunt = cci
End If
Next cci
For t = 1 To columnCOunt
Range(Columns(t), Columns(t)).EntireColumn.Select
    Selection.Replace What:="null", Replacement:="", LookAt:=xlPart, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
Next t