The best code is the code you don't need to write. Build only what you need (YAGNI) and introduce abstraction to avoid duplication (DRY). My rule is don't ever do the same thing three times (though I sometimes enforce it at two). Conversely, if you find you no longer need something (no matter how clever it was) delete it. It will only confuse you or whoever else is working on the system later.

If it truly is so clever it must be saved, throw it on your github account and reference it another day when you may need it again. Regardless, get everything that isn't needed out of the code base.