Rainboe does indeed come with a toxic health warning! It's designed to combat the perennial problem of seeing out of the windscreen in heavy rain, particularly on the approach, with the wipers flailing. It was contained in a silver cylinder, plastered with health warnings, and located on the rear bulkhead of the flight deck on the brand new Boeing 737-200 series that I lowered myself into the left-hand seat of, on an early command/conversion sector. There was an ugly dark smudge all up the windscreen. I groaned:
"Some daft sod's gone and sprayed Rainboe all over this windscreen when it wasn't raining. Can't some people read the manual! Sheesh!!"
"Yes," said the gravelly-voiced training captain in the right-hand seat ... "my profound apologies ... I did that yesterday!"
That was the start of an entertaining day out, during which the previously helpful training captain, became thoroughly unhelpful, the first officer of your worst nightmares, in fact. I duly fell into numerous elephant traps! At the post-flight debrief, the training captain promised to put a five second time delay on his index finger, on the Rainboe button, if I promised to put an equivalent time delay on my mouth! Then we had a good laugh, and went off to the pub.
The engineers said that the best way of getting the Rainboe 'goo' off the windscreen, was a liberal application of Coca-Cola, apparently.
The nimble 737 was 'gunnable' for a rapid departure, as described. However, trying the same tactic on the DC-10 was liable to have you shuddering straight on, most especially in the wet!