i bet someone else already suggested this as feature.

the possibility to delete topics after the trade is done

Hi squish,

This has been suggested for over 15 years, unfortunately this won’t be implemented as it is a right reserved for staff,

You can look at the list of previously suggested ideas to Close a topic here : https://forums.d2jsp.org/index.php?act=Search&c=8&r=96207310

This is correct. After a trade is completed just let the topic fade away.