https://www.gutenberg.org/cache/epub/26184/pg26184.txt
Simple sabotage is often an act which the citizen performs according to his own initiative and inclination. Acts of destruction do not bring him any personal gain and may be completely foreign to his habitually conservationist attitude toward materials and tools. Purposeful stupidity is contrary to human nature. He frequently needs pressure, stimulation or assurance, and information and suggestions regarding feasible methods of simple sabotage.
Forget to provide paper in toilets; put tightly rolled paper, hair, and other obstructions in the W. C. Saturate a sponge with a thick starch or sugar solution. Squeeze it tightly into a ball, wrap it with string, and dry. Remove the string when fully dried. The sponge will be in the form of a tight hard ball. Flush down a W. C. or otherwise introduce into a sewer line. The sponge will gradually expand to its normal size and plug the sewage system.
Last couple pages are best but do not copy easily on mobile.