Using expired makeup products can be harmful to your skin and overall health. Here are some products you should absolutely avoid using past their expiration date:

1. Mascara: Mascara has the shortest lifespan among makeup products, typically 3-6 months. The moist environment inside the tube is a breeding ground for bacteria, which can lead to eye infections.

2. Liquid Eyeliner: Like mascara, liquid eyeliner also has a short lifespan of around 3-6 months. The risk of bacterial contamination is high due to its liquid consistency and proximity to the eyes.

3. Foundation: Depending on the formulation, foundations can last between 6 months to a year. Using expired foundation can lead to skin irritation, breakouts, and infections.

4. Lipstick and Lip Gloss: These products typically last around a year. Using expired lip products can cause dryness, irritation, and even infections.

5. Cream-based Products: Cream blushes, eyeshadows, and other cream-based products usually last around 6-12 months. The high moisture content in these products makes them susceptible to bacterial growth.

6. Powders: Powdered products like blushes, bronzers, and eyeshadows can last up to 2 years. However, using expired powders can lead to skin irritation and breakouts.

7. Sunscreen: Sunscreen is typically good for up to a year. Using expired sunscreen can lead to decreased sun protection, increasing the risk of sunburn and skin damage.

Remember, these are general guidelines. If a product changes color, develops an odd smell, or changes texture, it's best to discard it, even if it hasn't reached its expiration date. Always store your makeup in a cool, dry place and avoid sharing it with others to prevent contamination.