If it is granulated sugar that has gotten too hard, the apple approach and a little paternce with work fine. If you totally lack patience and you are safe around hand tools, then using the happen on the sugar (if it is double bagged) will work. Use a laminated cutting board underneath for safety.
Sugar can be dissolved into water when low heat is applied over several hours. Do not allow the water to boil away or you will have burnt taffy permanently attached to your pot. If left unattended even longer, copious smoke and a real fire can result with disastrous consequences including damage from smoke and possibly fire damage as well.
Start with the safest, slowest method. If you can’t cope with that then for goodness sake either let someone else deal with it or throw the sugar away.
As for the crackers, if they don’t smell rancid and it there is no chance the crackers have been visited by rodents, then the cracker crumbs can be used in recipes that call for such an ingredient. If you are not sure they are still fit for human consumption, then put them in a bird feeder or on your lawn, far enough away from any tiny points of entry for tiny critters – you do not want to make mice, squirrels or rats feel too welcome around your house.