I would go with finalize. However I think it is a little bit dependent the exact use case: e.g. If you use it mainly to to release resources, close connections, files then release would be more meaningful.
If you are looking for a notion for general use, or standardize, I would choose some less meaningful, something with no special meaning like release, or remove.
The concept of init vs (whatever) is similar to (constructor vs destructor), or in java finalize.
(Note: If the language has the concept construct and destruct objects, its little or no need to use init(). )