Removing stale app reserved metafields

[SteveKaran]

While working on an app, I came across an interesting scenario, so I thought I'd run it by the community.

If your app uses app-reserved metafields (i.e. created and accessible only by the app), but then the app gets uninstalled and/or permanently deleted (yes, even from the Partner Dashboard) without cleaning up via uninstall webhook, how can any leftover/stale app-reserved metafields be deleted? 🤔