A temporary odditiy for the W10, during a mid 60s period, was the Ops room oven and the 'chippies' pencil being essentials. The batch of ignitor plugs were only good for one start without 'being fixed'. As soon as the morning mushroom hunt (test flight) was finished, the plug was removed, the 'sparky bits' heavily rubbed with a thick lead pencil and then 'baked' for 10 minutes in the oven. Once done, it was good for one more start !
This was how it was done at Thorney - don't know about other flights.