I'll give this penetrating oil a five star as opposed to a five because I haven't have the chance to test it on serious rusted parts like bolts and nuts, but that'll be coming up soon. I like the fact that it doesn't leave a smell...none at all...as opposed to WD40 and especially kroil penetrating oil. Both WD40 and kroil are effective in what they are designed for, but they can be harmful to the skin and health if precautions are not taken, especially when it comes to kroil. This oil, CRC, is odorless, colorless and made with safer ingredients. Having said that, the fact that is odorless and clear and safe for use in food processing equipment may create an issue if not handled properly. If you transfer this oil to smaller container, make sure the new container is labeled with its content as to prevent someone from accidentally using it as cooking oil.I was dealing with a jammed screw on an espresso machine group head. I wasn't sure if something food grade would work, but this did the trick. It takes a few applications and a couple minutes to work, but that's the same as any other penetrating oil working on stuck parts.Looking at the SDS on their web site, I think this is actually the same thing as their "Food grade machine oil", but that's not a complaint.I got this just to have a light lubricant / penetrating oil that's less toxic than things like WD-40. It works fine. Not sure it's an especially good value for the price, but I've not seen anything comparable for less. Drugstore mineral oil is a heavier viscosity and less convenient to dispense.If you do plumbing you need this product. Think edible WD40. It's the best for loosening up stuck valves, dried up O rings, etc. Just spray it on/in, let it soak for an hour to over night and what ever crusted/rusted part comes right apart. All without contaminating water system. Have used for a few years now and can say it works as well and as fast as WD 40 or PB catalyst.Seems to work as well as any other penetrating lube, except it doesn't smell like it's going to give me cancer. Oh, and it frees stuck bolts better than WD40.Great productThis food grade oil works great on our equipment.Great product, worked on deli and home appliances described!