gistfile1.txt

Meters can be listed with:

curl -i -u [apikey]: https://api.boundary.com/[org_id]/meters

And deleted with:

DELETE https://api.boundary.com/[org_id]/meters/[meter-id]

Delete with curl is, e.g.: 

curl -X DELETE -i -u [apikey]: https://api.boundary.com/[org_id]/meters/[meter_id]

So if you can cross reference the list against your inventory from AWS, you can use the above API request to cleanup old meters.

The meter manager API documentation, including the structure of responses from both of those endpoints is here (you'll need to log in to access it): https://app.boundary.com/docs/metermgr