Until now, manufacturers requiring secure containment of liquids and creams in glass packaging have tended to rely on steam capping. This process is expensive, time-consuming and not necessarily effective. The caps are also impossible to remove by hand for anyone with limited grip strength.
To improve shelf life, some go to the added expense of inserting a plastic shive, which acts as a bung. Even then, there is no guarantee that the seal will be airtight (hermetic) or watertight. And there is a particular problem when products with a high oil content penetrate the neck area, as that makes the seals useless.
A much more cost-effective option is