close your eyes grit your teeth and think of the freed up space!!. or do what i do and fire everything onto cd/dvd. sometimes i go through old renders and can  see them in a different light because i may have learned a new technique which can add something to it. so in answer to your question...no i cannot distance myself, and lack the courage to throw away much of what i have created (unless it really bugs me!)also its a good way of backing up mats/skies and objects that i like.