Yes. It's a worst case scenario. Someone took the longest bare aluminum seatpost they could find, stuck it as far down the seat tube of a nice butted MTB frame as it would go, left it in the rain for probably ten years, then put it out on their front lawn with the garbage for me to find. Ammonia does not work. It is too far down to saw it all out. Even when I saw it apart, it stays stuck to the seat tube.