What can be effectively removed from a test specimen using vapor degreasing?

Vapor degreasing is a cleaning process that utilizes the vapors of a solvent to effectively remove organic contaminants such as oils and greases from surfaces. The method is particularly effective for removing oils because the solvent vapor can penetrate into small crevices and displace the contaminants without the need for aggressive scrubbing or abrasion.

The solvent used in vapor degreasing typically condenses on cooler surfaces, where it can dissolve the oil and other organic residues, allowing them to be wiped away easily. This technique is especially useful in precision parts cleaning, such as in the manufacturing and automotive industries, where the presence of oil can negatively affect the functionality and performance of the components.

While vapor degreasing is excellent for removing oils, it is not suitable for removing substances like paint, rust, or water. Paint removal usually requires more aggressive chemical strippers or abrasion due to the paint's adherence to the surface. Rust, a corrosion product, often necessitates mechanical or chemical methods specifically designed to dissolve or remove rust layers. Water, being a polar substance, does not effectively mix with the non-polar solvents used in vapor degreasing, making it an inappropriate candidate for this cleaning method.

Thus, the choice of oil as the correct answer reflects