Why is it considered necessary to nail down the lid of a coffin..?
This was very hard to search on line because so many of the sites do refer to cigarettes or just the saying “another nail in the coffin”. I did find some references to jumping into the grave after the funeral to nail the coffin shut. And I also found references to how some manufacturers will tell you that the high end coffins have seals that will preserve the body (which isn’t true). So, my guess is that at least in some cultures, the coffin was nailed shut for this reason. I then found this which I thought was interesting: For the same reason that it was once the custom in Ireland to remove the nails from the coffin immediately before lowering it into the grave (in order that the dead might have no difficulty in freeing themselves on the day of Resurrection), so we find that the shroud or winding sheet was often loosened from the feet and hands, lest its tight folds should prevent a speedy egress at the all important moment. A special costume for burial was provided, and in some cases
