When I was a kid, I remember seeing a display of the ME 163 Komet rocket fighter at the Dayton Air Force Museum.
They had one on display that had been captured. Years after the war when it was being restored for display, they found a sharp stone wedged between the fuel tank and a strap that held it in place. Neatly penciled next to it was a French flag, and writing that said something like "Live Free or Die" in French.
A slave laborer had sabotaged it so vibration would make the fuel tank leak! That was probably why so many ME-163s blew up in flight.
That’s if you were lucky...the Komet’s fuel and oxidizer (concentrated hydrogen peroxide?) were nasty stuff.
I remember reading one instance of a Komet that suffered a severed fuel line (perhaps due to an aborted take-off?). By the time ground crewmen managed to get to the plane, the pilot had literally been dissolved in his seat.
The hydrogen peroxide tanks at the launch site could hold enough for 15 launches. So they built ready use V-1 magazines on each side of the launch track- an 8 unit one and a 7 unit one.
When RAF reconaissance photographed the launch sites, the Brits correctly guessed the reason for the difference in size, which told them the size of the missile and the number of ready use rounds.
The Germans could have avoulded that by being a little less efficient and using 2 eight unit magazines.