newbie forum question: how to "close a discussion"

great to hear from you Dan,
i have gotten some replies to my forum questions that have gotten me over various humps and helped me greatly. seeing as i have never joined a forum before i did not know if i had any responsibilities to manage or close these older posts. Would you suggest letting them remain as they are so they can grow or die a natural death? ...i want to make sure im a responsible contributor here. ...am i supposed to close or end a post after a given time?

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a side note to thank you for your work:
as a talented artisan up in Boston sometimes even excellent art&craft can become rote. The video of your recent lecture at the "The General Society..." reinvigorated my batteries with exciting fire. I have ordered a few of your texts and have been greatly encouraged by your style of communication (it makes me miss my northeast NJ home). I too am surrounded by hundreds of the old books in divers subjects. And I was immersed in these very books when you referred to your study of the dead men in your videos. I felt great endorsement and peace about my daily pursuit of knowledge. Thank you, it hit me like a courageous "YES!"

"I GIVE you the end of a golden thread;
Only wind it into a ball,
It will lead you in at Heaven’s gate,
Built in Jerusalem’s wall.…"
-william blake

most sincerely,
matthew rogers
p.s. all my radiators here are the civil war gun barrel variety.