Shipping containers for porous masses may include a bottom lid having a rectangular lid bottom and four bottom rims that are each continuous with the lid bottom; a tray comprising a tray bottom and four tray sidewalls that are each continuous with the tray bottom defining an interior with an open top; and a top lid having a rectangular lid top and four top rims that are each continuous with the lid top, wherein the tray is configured to be placed on a bottom lid with the bottom rims surrounding a portion of the tray with a top lid placed over the top of the tray with the top rims surrounding a portion of the tray.