The intentions were good of my brother-in-law’s wife to collect the emptied jars from the bar and use them to preserve herbs and other dry food that is normally sold here in small plastic bags and once opened immediately gets humid in this tropical sea climate. So the point of re-using the jars is to be able to close the lid properly, so no humid air comes in.
Those vacuum-closed jars are often hard to open, at home I am using a Swedish tool that looks like a bottle-opener of hard plastic, or simply a spoon to get little air under the lid to then be able to turn the lid easily and open the jar.
Cooks and barmen here however tend to get the work done quickly without changing the tool in their hand to open the jar in a sustainable way. Take a knife and smash some holes into the lid!