the tank and place it by hand, rather than throw it, thus the adhesive could very easily stick to their uniform in the process; the user would then be placed in the unenviable situation of attempting to pry the grenade loose whilst still holding onto the lever. It was also discovered that as time passed the nitroglycerin began to deteriorate and become unstable, which made it even more difficult to use. As the grenade was a short-range weapon, users were trained to hide in a trench or other place of concealment until the tank went past them, and then to stick the grenade to the rear of the tank, where its armour was thinnest. Users were relatively safe from a few yards away, as long as they were not in line with the handle when it detonated. The Mark II design used a plastic casing instead of glass, and a detonator instead of a cap. Operational use According to a War Office training pamphlet dated 29 August 1940, the sticky bomb should be regarded as a portable demolition device which can be "quickly and easily applied". It was reckoned to be effective against armour of up to thickness and was suitable for use against "baby" tanks, armoured cars and the vulnerable points on medium and heavy tanks. The safest and easiest application was simply to drop it from an upstairs window; otherwise, it could be used in an ambush of mobile tanks moving along a narrow road or in an attack on tanks parked up for the night. The sticky bomb could be either thrown or applied in place by hand, in the latter case, the advice was to use sufficient force to break the glass thereby creating a greater area of contact resulting in a more effective explosion. Finally, there was also the option of placing the bomb first and then pulling out the pin at a safe distance by means of a length of string. Macrae credits the Australian Army with developing the technique of applying a sticky bomb directly onto a tank instead of throwing it from a relatively safe distance. Since the bomb used a blast effect, it was safe to do this and walk away provided only that the bomb's handle was pointing away from the bomber – the handle would be shot away from the explosion "like a bullet." Macrae gives no date for