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If you want a cleaner forum, then you need to start just with yourselfs ( the managers of the bounty ), perhaps it is time to act administration forum, you can make the recommended form of holding the Bounty, which must be observed by all managers, that reports should be sent only to the form and not in the topic.
All topics that are opened by managers should be with self moderation and all reports that are not sent to the form will be simply deleted. I think the idea is clear...
Perhaps enough to blame only the participants? Each Manager has different conditions, why is it necessary?
Make the same conditions for all managers, it will reduce the load on the forum and reduce the number of senseless messages.