Good evening Tim,

The Keens Mustard tins do not have a lid gasket. The larger container has a top that comes off well, the smaller containers top is difficult to remove. They would both need to be sealed with tape after the PSK stuff is added.

Some tobacco tins have a small rubber gasket seal in the lid (nice), most candy/mint tins do not.

I have an addiction to PSK container collecting!

Mike