If it's your ultimate goal to be better at throwing things out, and not just to have less stuff short-term, you're actually punishing yourself for engaging in the desired behavior when you withhold credit for doing so (or spend any time on negative feelings as a result of doing the task), which seems counterproductive.
You might find an auxiliary habit of patting yourself on the back (or similar small reward-feeling behavior) when you do your task to be more helpful!
This is the public group instrumental rationality diary for December 1-15.
Thanks to cata for starting the Group Rationality Diary posts, and to commenters for participating.
Immediate past diary: November 16-30