Do speaker cables need a burn in period?

I had some KK silver KCAG interconnects that sounded a little harsh so I cooked them for 24 hours but no change. I then cooked them for a solid week. Wallah, the harshness was gone. Now what happened? 1. I might have cleaned the contacts by moving them. 2. Some static may have bled out. 3. The power grid may have been cleaner. 4. I might have been in a cheerier mood or by waiting and being more optimistic.