I don't tend to use a lot of brown sugar. Infact, it probably takes me 6 months to go though one bag of it. Unfortunatly that means that a lot of times, my brown sugar "dries" out and gets hard. I never knew what to do about this till I saw my Mom open her brown sugar container one day. I saw something in with the sugar. When I asked her what it was, I was supprise to find out it was a piece of bread.
Her sugar had gotten hard and so she put a piece of fresh bread in with it. But when she took the bread out a couple days later, the sugar was once again soft and the bread was hard and stale. The moisture goes out of the bread and into the sugar. So instead of throwing out a whole bag of hard brown sugar, you just throw out one piece of bread. This works with home made bread, white, wheat, or any other type you can come up with.
It also works for hard cookies. Place one to two slices of fresh bread in a sealed container or plastic bag with cookies that have gotten a little over baked or have sat out and gotten hard. Makes for soft, chewy cookies! Yum!