lacre-refers to the expression : wax-like solid paste, usually reddish, which is pressed in the form of bars,
It is a paste or gum based on rosin and turpentine, is used to place it as a safety seal.
In Lunfardo is "blood", by the color of the material to seal or sealing, which was vermilion precisely because it represented the blood of Christ.
LACRE:PRECINTO OR TURPENTINE, LACQUER, AND MADE WITH RUBBER SAFETY SEAL.