How do I remove the characters?

Question

How do I remove special characters and alphabets in a string ?

 qwert1234*90)!  \' this might be my cell value

I have to convert it to

Answer 1

Non-re alternative;

Public Function fmt(sValue As String) As String
    Dim i As Long
    For i = 1 To Len(sValue) '//loop each char
        Select Case Mid$(sValue, i, 1) '//examine current char
            Case "0" To "9", " " '//permitted chars
               '//ok
            Case Else
               Mid$(sValue, i, 1) = "!" '//overwrite char in-place with "!"
        End Select
    Next
    fmt = Replace$(sValue, "!", "") '//strip invalids & return
End Function

For:

?fmt("qwe123 4567*. 90") 
123 4567 90