MX stems are made of acetal aka delrin aka POM



While similar, they are all a bit different.None handle acids and oxidation well, however POM isvulnerable to chlorine, which is why POM kitchen knives (and pocket knives) shouldn't be put in the dishwasher. Even the small amounts used in drinking water will cause stress fractures in it. This is made worse when the water is hot. Delrin and Acetal do not experience this, which is why some computer water cooling systems use it in their construction, if you were to make it from POM, your computer would soon be flooded.In other words, don't clean your POM keycaps in the dishwasher like you can with IBM keycaps.They may survive a couple times, but eventually they will break down.