Unless this is a shared mailbox or you have more than one account using the mailbox then all the items in the default sent folder are from you, in which case you can remove the references to strAddress in the following macro i.e. Change
If olItem.SenderEmailAddress = strAddress And _
olItem.BCC = strBCC Then
to
If olItem.BCC = strBCC Then
Sub DeleteSent()
Dim olItems As Outlook.Items
Dim olItem As Outlook.MailItem
Dim i As Long
Dim strAddress As String
Dim strBCC As String
strAddress = "me@myaddress.com" 'Your e-mail address
strBCC = "someone@somewhere.com" 'The BCC address
Set olItems = Session.GetDefaultFolder(olFolderSentMail).Items
olItems.Sort "[Received]", True
For i = olItems.Count To 1 Step -1
Set olItem = olItems(i)
If olItem.SenderEmailAddress = strAddress And _
olItem.BCC = strBCC Then
olItem.Delete
End If
Next i
Cleanup:
Set olItems = Nothing
Set olItem = Nothing
lbl_Exit:
Exit Sub
End Sub