Until recently, you would always find brown sugar in those annoying little boxes. Aside from being much too small for any practical baking, the sugar itself was held in a lame wax paper bag that never really closed well. Then some brilliant marketer figured out that the real way to distribute brown sugar was to put it in re-closeable plastic bags. Which is all good, except that they skimped on the plastic a bit as they are both too thin, and hard to open (not enough finger grip). So when I need to restock my brown sugar I empty the contents into a sturdy freezer Ziploc baggy. It will stay nice and soft (so long as you close it completely) and has the added advantage of being perfect to fill measuring cups. You simply drop the cup right into the bag then scoop and press in the sugar from the outside. Your hands stay clean and your sugar fresh.