Sprinkle with bicarb, leave for a while, then make up a lemon juice and bicarb mix, give it a good swoosh and wipe down. Leave to dry. Result, a sweet smelling bag.
Or a wipe out with nicely scented fabric conditioner.
If it's notplastic, a short, gentle wash in the washing machine, or if it is, a wash in the machine, much as you might do for trainers might be OK.