Catnip infused paper bags

I bought a package of 2 catnip infused paper bags because my cats are incredibly spoiled. But, they do love these things. They are just a paper bag that has been "infused" with catnip. They went nuts for it and are still using it, 2 weeks later. I am not sure how long the catnip lasts but I sprinkled a little fresh nip inside it yesterday and they went for it right away. I don't live in a city that uses paper bags anymore otherwise I would just make my own - but again, my boys are so spoiled, I obviously had to buy this.