I can provide some general guidance.
Before microwaving any product, including a Philips Avent bottle cover, you should always refer to the manufacturer's instructions and guidelines provided in the product's user manual or packaging. The user manual will have clear instructions on whether the bottle cover is microwave-safe or not.
If the user manual indicates that the bottle cover is microwave-safe, then you can microwave it following the recommended guidelines. On the other hand, if the manual does not mention microwave use or advises against it, then it's best to avoid microwaving the bottle cover to prevent potential damage or safety hazards.
To ensure safety and prevent damage, make sure to follow the manufacturer's guidelines regarding the use of the bottle cover with microwaves or any other heating methods. If you're unsure or unable to find the relevant information in the user manual, consider contacting Philips Avent customer support for clarification.