Theoretically you might be able to teach a dog to NOT go somewhere, it takes a VERY long time and is VERY difficult to do, but forget it with a cat. Nothing, NOTHING you can spritz, sprinkle, spray, disperse or otherwise scatter about is going to stop a cat from going where it wants to go, and while they can be trained for some things, the concept of "KEEP OFF" just doesn't really compute with most cats.
WHATEVER YOU DO, DO NOT SCATTER MOTH BALLS AROUND, THEY ARE LETHALLY TOXIC TO HUMANS AND ANIMALS!
Get the shit that you don't want the animals getting into in a room or closet you can keep closed, seriously. Look, lifetime animal owner/breeder/rescuer her, there's some things that it's just NOT worth fighting the tide over. You live with animals you have to realize that THEY ARE ANIMALS, not little furry people. Stuff doesn't mean shit to them and one piece of stuff is just as inconsequential as the next piece of stuff.
It's just like having a toddler, you can't teach a toddler to keep their sticky paws off things, you get the things away from the toddler, SAME THING.