Several outlets report that people may notice crusty, yellow discoloration on toenails when wearing sandals or flip-flops after winter. The articles frame the issue as a common foot-care concern that becomes more visible during warmer weather. They cite the role of everyday habits and foot conditions that can contribute to toenail changes, including exposure that may promote moisture and friction around the feet and toes. The reporting also includes guidance on how to address the problem, emphasizing practical steps for home care and hygiene. While the pieces do not present a single definitive cause, they discuss the pattern of symptoms—such as yellowing and crusting—and point readers toward measures intended to reduce irritation, improve cleanliness, and support recovery. Overall, the articles present the toenail discoloration as a frequent complaint that can become noticeable in summer and outline care steps described by a medical contributor, urging readers to follow the recommended approach.