Clean pulls are the best way to build your traps. You can use a wide grip and change the variation to a snatch pull. You can do them from a variety of rack heights. And you can do them with a pause at the top (for half a set or the whole set) to increase trap activation.
Arnold Schwarzenegger did a lot of things wrong. He performed endless sets of leg extensions thinking that he was "cutting up" his thighs. He believed that pullovers would spread the rib cage and pull-ups would widen the shoulder girdle by spreading the scapulae.