Empty your suitcase of anything you left inside last time you traveled. Remove all your luggage tags to make sure your suitcase doesn't get routed to the wrong place.
Brush the surfaces of the suitcase both inside and out with a dry brush to loosen any dirt.
Use a handheld vacuum or the attachments on your full size vacuum to vacuum out the inside of the suitcase. Be sure to vacuum all of the little pockets.
Take a damp cloth and a mild soap and wipe the surfaces of the bag to wash it. Gently rub in a circular motion.
Rinse off any remaining soap using fresh water and a clean rag.
Spray the inside of the suitcase with a fabric freshener or your favorite perfume or cologne.
Allow the suitcase to dry thoroughly before packing it. Leave the top of the case open until fully dry.