U.S. Air ForceSenior Airman Joshua Thomas, 33rd Aircraft Maintenance Squadron nondestructive inspection technician, applies a fluorescent penetrant chemical to an aircraft part May 5, 2021, at Eglin Air Force Base, Florida. This method, also known as Penetrant Method C, removes excess penetrant by hand wiping the surface with a cloth moistened with solvent remover to potentially reveal surface cracks. (U.S. Air Force photo by Airman Colleen Coulthard)