(1) Put metal dust or filings, fine sand, ground glass, emery dust (get it by pounding up an emery knife sharpener) and similar hard, gritty substances directly into lubrication systems. They will scour smooth surfaces, ruining pistons, cylinder walls, shafts, and bearings. They will overheat and stop motors which will need overhauling, new parts, and extensive repairs. Such materials, if they are used, should be introduced into lubrication systems past any filters which otherwise would strain them out.
(2) You can cause wear on any machine by uncovering a filter system, poking a pencil or any other sharp object through the filter mesh, then covering it up again. Or, if you can dispose of it quickly, simply remove the filter.
(3) If you cannot get at the lubrication system or filter directly, you may be able to lessen the effectiveness of oil by diluting it in storage. In this case, almost any liquid will do which will thin the oil. A small amount of sulphuric acid, varnish, water-glass, or linseed oil will be especially effective.
(4) Using a thin oil where a heavy oil is prescribed will break down a machine or heat up a moving shaft so that it will “freeze” and stop.
(5) Put any clogging substance into lubrication systems or, if it will float, into stored oil. Twisted combings of human hair, pieces of string, dead insects, and many other common objects will be effective in stopping or hindering the flow of oil through feed lines and filters.
(6) Under some circumstances, you may be able to destroy oil outright rather than interfere with its effectiveness, by removing stop-plugs from lubricating systems or by puncturing the drums and cans in which it is stored.
(c) Cooling Systems (1.) A water cooling system can be put out of commission in a fairly short time, with considerable damage to an engine or motor, if you put into it several pinches of hard grain, such as rice or wheat. They will swell up and choke the circulation of water, and the cooling system will have to be torn down to remove the obstruction. Sawdust or hair may also be used to clog a water cooling system.
(2) If very cold water is quickly introduced into the cooling system of an overheated motor, contraction and considerable strain on the engine housing will result. If you can repeat the treatment a few times, cracking and serious damage will result.
(3) You can ruin the effectiveness of an air cooling system by plugging dirt and waste into intake or exhaust valves. If a belt-run fan is used in the system, make a jagged cut at least half way through the belt; it will slip and finally part under strain and the motor will overheat.
(d) Gasoline and Oil Fuel Tanks and fueling engines usually are accessible and easy to open. They afford a very vulnerable target for simple sabotage activities. (1.) Put several pinches of sawdust or hard grain, such as rice or wheat, into the fuel tank of a gasoline engine. The particles will choke a feed line so that the engine will stop. Some time will be required to discover the source of the trouble. Although they will be hard to get, crumbs of natural rubber, such as you might find in old rubber bands and pencil erasers, are also effective.