https://medal.tv/games/minecraft/clips/J0lEQ__pGtqpq/d1337cpyHquF?invite=cr-MSxIQjIsNzk3MjE5MTEs

^ video :)

by adding more than one lamp in a barrel with olive oil you're able to dupe them. Then you can shift click them out and they won't be consumed at the top of the barrel. afterwards you can smelt them again.

the whole stack will have the tag "Filled" but only the first lamp of the stack is actually filled. :D

hope this helps!