Marvel Mystery Oil is a powerful, multi-purpose oil additive that has been around since 1923. It can be used for everything from engine cleaning to rust prevention. But one of its most popular uses is as an engine sludge remover and cleaner. Sludge build up in engines is caused by the natural condensation and accumulation of unburned fuel, dirt, and other debris over time. If left untreated it can lead to serious performance problems such as decreased power output or even total engine failure. Thankfully Marvel Mystery Oil can help clean out this sludge quickly and easily! Just add a few ounces into your vehicle's crankcase every 3 months or so (or whenever you change your oil) to keep your engine running smoothly. The product is safe for use on both gasoline and diesel engines and will break down any gunk that might be clogging up the works without damaging any internal components or seals unlike some harsher chemical treatments which could damage sensitive parts like rubber gaskets or O-rings. Plus, you don't need any special tools or equipment; just pour it in through the dipstick tube! So if you're looking for an effective way to get rid of stubborn sludge buildup in your vehicle's motor then give Marvel Mystery Oil a try – it just might save you from costly repairs down the road!