Dear Mister Monty 55:
Well this rather idiotic experiment performed by this crazy scientist'was done on a few Unopened square tins in order to try out and see if the tins inside vacuum would increase,and apparently this experiment did have some success,judging by the general appearence of these few tins which were involved in this nonecence experiment,At first glance they got flatter,something like the lid went closer to containts yet like the seal was improved. Despite of this doubtful success,I wouldn't recommend using this method too actively,possibility is that even 30 sec.'hot boiling seance'has negative affect on the tobacco taste+ moisture content,hardly but it might.Remains to be seen now,yet many classic flakes are steam pressed at the factory,and Now I will leave these tins alone sitting on my cabinet for some extented period and then pop open for sampling.