How to avoid counting blanks in a list

I have received this VBA code to that search a column for unique numbers.
These numbers are then stored in a string:

Dim rCel As Range, clFilter As Collection
Dim iCntr As Integer
Dim sMsg As String

Worksheets("Sheet1").Range("A9:A65536").Select
Set clFilter = New Collection

On Error Resume Next
For Each rCel In Selection
clFilter.Add Str(rCel.Value), Str(rCel.Value)
Next rCel

For iCntr = 0 To clFilter.Count - 1
If iCntr < clFilter.Count - 1 Then sMsg = sMsg & clFilter(iCntr) &
", "
If iCntr = clFilter.Count - 1 Then sMsg = sMsg & clFilter(iCntr)

Next iCntr

However, this code also counts blanks.
How do I avoid adding the occurences of blanks (represented by a zero) in
the sMsg string?


Thanks

Frank