Slam against forehead to open.

Aluminium, my dear boy. If you can’t finish words properly, you’ll never make it through your first incantation.

You fool, don’t you know that aluminium cancels out any form of magic?

Your potions will go innert as soon as they touch the can!

Did you master not teach you about the arcane properties of the metals??

Stupid apprentices, always thinking they made a brand new invention. There’s a reason we use glass vials, got it?