Heh, I remember when, as a trainee, I was told about that. I have a vivid imagination, so...I paid attention to that one. In retrospect, the only time I was even near that kind of thing was when a guy got sucked into a Tomcat. He lived, because the pilot saw it and instantly shut the engine off, but the guy’s tools went through the compressor section.
I had a chance to look at the engine while it sat there waiting to be sent off the ship, and that compressor was ugly, and there were some holes where the tools went out the side of the engine casing.
In Nam, the way the Huey mechanics would clean the turbine blades was to spin up the engine and then throw in a bushel basket of walnut husks.
Clean as a whistle.