Core Viewpoint - The recent incident involving a beauty blogger using expired eyeshadow has sparked discussions about the shelf life of cosmetics, particularly in the context of summer's high temperatures and humidity, which pose risks to the stability of beauty and skincare products [1] Group 1: Identifying Expired Cosmetics - Powder eyeshadow can be identified as expired if it shows signs of clumping, mold spots, or emits an unusual odor [3] - Cream eyeshadow may indicate spoilage through oil separation, water formation, or deepening color [3] - The claim that household UV lamps can detect expired eyeshadow is refuted, as these lamps cannot comprehensively assess microbial contamination or oxidation within the product [3] Group 2: Proper Storage Practices - The "three avoidance" principles for summer storage of cosmetics include avoiding light, heat, and moisture [3][4] - Light exposure accelerates the decomposition of effective ingredients, necessitating storage in dark places even for opaque packaging [3] - High temperatures can increase chemical reaction rates and microbial activity, with a recommendation to keep products in cool, ventilated areas below 25°C [3] - Humidity fosters microbial growth, and caution is advised against storing products in damp areas or frequently opening refrigerated items, which can introduce moisture [4] Group 3: Safe Usage Recommendations - It is advised to use makeup tools exclusively to prevent cross-contamination, especially for eye products [5] - Caution is recommended when switching to new products, as skin may need time to adapt, and allergic reactions can occur [5] - Expired or potentially spoiled products, particularly those used near the eyes or lips, should be discarded immediately to prioritize health over waste [5]