Originally posted by 4L1-S:

I never see permanently untradable items; only temporarily untradable ones, which are untradable due to being purchased on the Steam Community Market or the Mann Co. Store; or due to being uncrated.

Never thought I'd get a response on a year-old thread.
http://www.tf2outpost.com/trade/29548793 I mean something like this.

Right now, there's tons of trades with untradable items littering the website.
That wouldn't have been a problem if you could have excluded untradable items from the search, but there's no such filter (suggestion for which was already submitted, but rejected for whatever reason).
Is there a reason to why untradable items are allowed to be added in trades? (excluding temporarily untradable items, of course)