Option Explicit

Sub MyMacro()
    MsgBox ExtractDigits("601A50B300")
End Sub

Function ExtractDigits(StrInput As String) As String
    Dim intLen As Integer
    Dim i As Integer
    Dim strTl As String, strT2 As String
    
    intLen = Len(StrInput)
    
    If intLen > 0 Then
        For i = 1 To intLen
            strTl = Mid(StrInput, i, 1)
            If strTl = "0" Then
                strT2 = strT2 & strTl
            Else
                strTl = Val(Mid(StrInput, i, 1))
            If strTl > 0 Then strT2 = strT2 & strTl
            End If
        Next
    End If
    
    ExtractDigits = strT2
End Function