[arethuza]

One of SOE's achievements around D-Day was introducing abrasive materials into the axle bearings of the trank transporters for the SS Das Reich division - they were stationed in the south of France and had to try to make their own way there rather than using transporters - which fortunately didn't go well.

An entire division of experienced and well equipped troops pretty much neutralised with some gritty powder in the right places....