prof
i figured you meant lav dafka, just wanted to clarify for SJ
i believe that most Poskim hold you should do mechira even if you have no chametz mamish that you know about. see haifagirls response from her Rabbi (whom i happen to know and is completely reliable)
but im not sure if your conclusion is correct as charlie would be mevatel the blios, and then he wouldnt own them during Pesach