Is there a way to do this now? I looked to see if I could recreate the volume, but it doesn’t show up under my app with fly volumes list. This would in particular be useful for clearing out buildkit cache.
You should be able to connect to your builder while it’s running, or up to 10 minutes after it has ran. This isn’t super practical though.
You can find your builder app this way:
flyctl apps list | grep fly-builder
and connect like this:
flyctl ssh console -a fly-builder-...
Its data folder is mounted at /data I believe.
Thanks. Out of curiosity, why doesn’t this builder app’s volume show up in the list of volumes?
It doesn’t show up if you flyctl volumes list -a fly-builder-...?
Volumes listing is per-app 
Ah right, that works. Might venture a PR for cache busting at some point.