The metal mask played a significant role for the colonial masters during slavery and it is used for 3 main reasons.
1) To prevent the enslaved from eating fruits such as apples, pineapples, oranges, cashews, bananas, plantains and sugarcanes etc while harvesting them, yet they were made to work consistently in all the plantation farms.
2) To stop the enslaved from chanting our African spiritual songs. Not only that those our spiritual and war songs affected the slave masters, it also motivated some enslaved to rebel and fight back not minding l0sing their lives.
3) To stop enslaved form teaching our African local dialects (languages) to their children…whereby destr0yed our dialects and forced them to learn foreign languages.
Last but not the least, to starve enslaved as a punishment in the slave camps. The mask prevented them from eating or drinking.
Sometimes the slave masters would f0rced an apple (a whole) into the mouths of enslaved before they wore the metal mask on them with the padlocks so that they couldn’t talk.

Eishi, people really had a bad heart. It reminds me of those slaves who were building the pyramid during those days without these modern tools