Sentence:  A slurry of 10 grams of powder in 100 milliliters distilled water was carried on a cotton swab and the panels scrubbed until free from <WSD>waterbreak</WSD> when rinsed. 
Meaning of the word marked with <WSD> tags:  The formation of beads of water on a smooth surface, especially when used as an indicator of impurities on the surface.