unable to get the text property of the characters class, no change to line causing error

Question

I have a sub that will be passed a column letter, and for row 2 to the last row of that column, extract only the numbers from the cells and overwrite the cells with those numbers.`

Sub ExtractNumbersInColumn(ColWithNums As String)

Dim Rng As Range, Dn As Range, nStr As String, n As Long
Dim wb As Workbook
Dim ws As Worksheet

Set wb = ThisWorkbook
Set ws = wb.Sheets("RefindData")

Dim rngStart As Range
Dim rngEnd As Range

Set rngStart = ws.Range(ColWithNums & "2")
Set rngEnd = ws.Range(ColWithNums & Rows.Count).End(xlUp)
Set Rng = ws.Range(rngStart, rngEnd)

For Each Dn In Rng

For n = 1 To Len(Dn.Value)
    If Dn.Characters(n, 1).Text Like "[0-9]" Then
        nStr = nStr & Dn.Characters(n, 1).Text
    End If
Next n

Dn = Val(nStr): nStr = ""

Next Dn

End Sub`

I am getting an issue with this line:

 If Dn.Characters(n, 1).Text Like "[0-9]" Then

with the error - "unable to get the text property of the characters class"

After doing a little research this problem appears with older versions of Excel. I am using 2003. However, the simplified version of this code:

  Sub MG31May23
Dim Rng As Range, Dn As Range, nStr As String, n As Long
Set Rng = Range(Range("A1"), Range("A" & Rows.Count).End(xlUp))
For Each Dn In Rng
For n = 1 To Len(Dn.Value)
    If Dn.Characters(n, 1).Text Like "[0-9]" Then
        nStr = nStr & Dn.Characters(n, 1).Text
    End If
Next n
Dn.Offset(, 1) = Val(nStr): nStr = ""
Next Dn
End Sub

Works fine, and that particular line is not changed.

Any ideas?

EDIT:

I have discovered that it does not like to look at a cell containing only numbers otherwise .Text will kick up a fuss. So the real question now is how can I alter this for it to be happy looking at cells that contain letters and numbers, as well as just numbers (but not do anything with obviously)

Answer 1

With help from the commenters, this section of code works better to perform the task of number extraction:

   For n = 1 To Len(Dn.Value)
    If IsNumeric(Mid(Dn.Value, n, 1)) Then
        nStr = nStr & Mid(Dn.Value, n, 1)
    End If
Next n