SP3 is the deepest penetrating oil you can buy. It was created after we decided that other products weren't working well enough for us. SP3 eliminates rust. All you have to do is spray the rusted item or area and wait a little while as our unique formula breaks down the corrosion. Remove the rust with a brush or scratch pad, then wipe the area clean. It is ready to paint at this point. There is no need to remove SP3 before you paint, just wipe the area with a dry rag. SP3 is so much more useful than just wiping out your rust problems. This deep penetrating oil will release parts that are frozen together and free up engines that have been stuck solid for years, even decades. SP3's low-viscosity formula lets it seep into every space in a part. Just as with dealing with rust problems, simply coat your problem project with SP3, step back and let this product penetrate deeply throughout. After a short time you will see results and will have freed up your frozen parts. Low-viscosity makes SP3 the deepest penetrating oil available. And the best use for SP3 is to unstick engines that are really stuck. Prepare your engine to get unstuck by removing all sparkplugs (or injectors if your engine is diesel) and draining any standing water remaining in cylinder with a suck nozzle inserted in sparkplug hole. Spray a 2-3 second burst of this deep penetrating oil into the cylinder and into the intake manifold of the engine. Let sit 24 hours. Then rock the car/truck back and forth OR bump the starter a few times after installing a fresh hot battery. That should do it, but if your project is a real problem, you may have to resoak the cylinder and intake manifold with SP3 and wait another 24 hours. If your engine is so stuck that even two treatments with this deepest penetrating oil find it still stuck, then give us a call. We have dealt with these tough projects for years and we can help you free that engine up.