German, American and British forces used "sticky bombs", shown in the movie by American troops using their socks as bags to be filled with plastic explosive and then coated with axle grease so that it would "stick" to an enemy tank. However, real magnets were often used, and the "sock" was actually some woven fabric, when available, and rather than putting the bomb on the tracks of a tank directly, this would only disable its movement but still allow the tank to fire. The surface of a tank was often too hot to use axle grease, which was not always available; if it was, the grease would simply melt and the bomb would slide off. Furthermore, manually placing a sticky bomb coated with grease gave away one's position and was tactically dangerous, not because the fuse might run out before it could be placed properly as shown in the movie, but because tank commanders, before engaging in battle, could see troops running from buildings or their hiding positions. Traditionally, the sticky bomb was weighted with magnets and dropped from the height of a building, where not only could the one who placed the bomb be less easily seen, but because the bomb was designed to stick on the top of the tank or turret, where its armor was the weakest, and this had the effect of sending the shock wave down through the tank, which would be blown apart from the inside, killing the crew instantly. Plastic explosive was more commonly used than dynamite, as PE (Composition "B") is a fast explosive and more effective than slower-burning dynamite, which did work but had the effect of "cooking" the enemy tank crew instead of vaporizing them. In either manner, being on the wrong end of a sticky bomb was a gruesome, horrible way to die.