Ecco il codice
Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
'Button6.Text = Me.elencopagine.Lines.Count
Dim stringa As String = "il mio <amico>antonio <ieri> è andato al mare"
pulitrice(stringa)
Me.TextBox2.Text = stringa
End Sub
Sub pulitrice(ByRef stringa As String)
Dim i1, i2 As Integer
i1 = stringa.IndexOf("<")
i2 = stringa.IndexOf(">")
While i1 >= 0 And i2 >= 0
stringa = stringa.Remove(i1, i2 - i1 + 1)
i1 = stringa.IndexOf("<")
i2 = stringa.IndexOf(">")
End While
End Sub