No, absolutely not. 3M Novec Engineered Fluids are very clean. The liquids are definitely not oily and are much thinner than oil (thinner than water actually). There will be no residue on any parts, such as boards, chips or cables. There is no need to clean up, and in fact your hardware will be cleaner than ever before (3M Novec is also used as solvent to clean during the manufacturing stage, thing of the inside of hard drives such as on the discs themselves). It's also non-toxic, doesn't harm the environment, and is non-flammable. There is no need to pump Novec like oil, so there are no noisy pump stations in the datacenter.