Grooming a community - How did you do it?

I think it’s time for me to let go of the members in my community who have been dormant for some time.

Before I deactivate them I thought it’d best to:

1. Warn them and give them the option to stay.
2. Set a timeframe for when I need to hear from them.
3. Ask what could make the community valuable.

Thoughts? What steps did you take to groom a community? What was the outcome?