Through contact-angle experiments in air and under water, it has been found that the nonpolar surface tension γ ad and the polar surface tension γsp of a smooth fluoropolymer surface could qualitatively reveal the behavior of staining in air and stain removal under water. The effect of temperature on staining and stain removal was also studied. Practical application of this work is to help define the surface properties of a coating of paint or textile finish and their relation to stain repellency and removal.