Which method is NOT recommended for removing grease from a penetrant test specimen?

Removing grease from a penetrant test specimen is crucial for ensuring accurate results in testing. Each method of cleaning has its benefits and drawbacks, particularly in terms of compatibility with the penetrants used in testing.

Hot water rinsing is not recommended because it may not effectively remove all types of grease, especially those that are more viscous or hardened. Additionally, using hot water could potentially affect the integrity or surface condition of certain materials, which could interfere with the penetrant's ability to effectively enter any surface defects.

On the other hand, solvent wiping, ultrasonic cleaning, and pressure washing can be more effective in thoroughly removing grease without leaving residues that could impact the test results. Solvent wiping can dissolve grease, ultrasonic cleaning can agitate and dislodge contaminants, and pressure washing can provide a thorough cleaning by applying forceful jets of water and/or cleaning solutions.

Thus, while hot water rinsing might be convenient, it lacks the efficacy and care required for effective surface preparation in penetrant testing.