I just checked the potions in a belt when upgraded to 1.10s.
If the belt gets deleted, the extra potions become "invisible". You can empty the potions out normally (drag them out from the first row), and they will all be there.
-rcv-
If the belt gets deleted, the extra potions become "invisible". You can empty the potions out normally (drag them out from the first row), and they will all be there.
-rcv-