Microwave-safe cookware and containers usually do not come with metal lids. The reason for this is that metal is generally not safe to use in a microwave. When microwaves come into contact with metal objects, it can cause electrical arcing or sparks, potentially damaging the microwave and creating a fire hazard.
However, some microwave-safe containers or cookware may come with lids that have small openings or vents made from non-metallic materials. These openings allow steam to escape and help prevent pressure buildup during cooking. It's important to ensure that these vents are specifically designed for microwave use and that they are in good condition to prevent steam from building up excessively inside the container.
If you need to cover food in the microwave, it's safer to use microwave-safe lids made of materials like microwave-safe plastic, glass, or microwave-safe silicone. These materials are designed to withstand the heat and energy produced by the microwave without posing any risks.
Always check the packaging or product labels to verify if the lids are microwave-safe and follow the manufacturer's guidelines for safe use. If you're unsure, it's best to use a microwave-safe cover or leave the container partially uncovered to allow steam to escape while heating.