Air tag battery change

Thanks for providing your solution.

A couple things to note from the image you provided:

1. There appears to be an excessive amount of debris inside the tag. This may have attributed to why the battery cover was difficult to remove.
2. The tag is using a Duracell battery. These batteries typically have a bitterant coating. Apple advises against using these types of batteries with their tags. However, a number of folks have used workarounds, including cleaning the battery with rubbing alcohol or lightly sanding them with some success.