If it were my cat, I would place him in a cardboard box with a nebulizer or an ultrasonic room mister then close the top to keep him in the box for 15 minutes 3 x a day. Put Colloidal Silver full strength in the nebulizer.
PS) Wear gloves. I suspect that once your cat finds out what you are up to, he may try to bite or scratch to avoid being placed into a box. I know how cats are. Be very careful.