I totally agree with not adding manual labor for you.

Perhaps a "hide" feature? And maybe further, if it gets hidden x times by users you could consider hiding old posts... but even if not, the ability for me to hide them for myself would reduce my own personal cognitive load.

It just kinda sucks to want to help and go to "Unanswered" to help but see stuff that is irrelevant (either by date or by subject matter or both).