registry with multiple portfiles

[db]

On 11 Jul 2017, at 18:40, db <iamsudo at gmail.com> wrote:
> While writing the portfile for py-ipaddr in vim I saved it and stopped the process, then installed/uninstalled the port and made some corrections in the portfile, repeat.

I tried this with another port while monitoring its registry folder and it creates a new portfile. Port install logs

Portfile changed since last build; discarding previous state.

Should I leave the old portfiles where they are? Is there any way to clean the registry portfile tree?