When you clean, organize or donate things it gives you a sense of accomplishment which helps with stress relief. It also allows you to be in a new and fresh environment. This convinces your brain that this is a new and different situation. In other words, you get a break on whatever was stressing you out. When you donate things, you are doing something good for someone else and therefore it gives you satisfaction and it makes you feel happier. That is why cleaning and organizing, though they can be a stressors, can also be big stress relievers.
