Oh it was a thought out planned revenge. The man was a pin the backside, we could never quite pin anything on him. My boss loathed the sight of him. For three days all the swarf from any grinding was carfully collected, used thinner was preserved, and talk was insigated in his hearing of that moaning contract I'd got to do over the weekend, got to fuel up Friday afternoon and take the tractor home, etc, etc,. We added a couple of pints of disiel to get the smell right then did a 'rush' job on Friday afternoon to get me away, forgetting to take the last can back inside. The plan was to stop the engine properly, so about a dustpan full of grinding swarf went in, most of it as I recall from the refurbishing of a liquid muck tanker going to Windsor Polo club.