With the substantial losses of native prairie habitat over the last century, research focusing on the restoration of prairies has become imperative in order to conserve these imperiled ecosystems and the biodiversity they support. On the Clatsop Plains in northwestern Oregon, there are only a few remnant patches of coastal prairie, which are vital for many species including the federally threatened Oregon silverspot butterfly (Speyeria zerene hippolyta). Building upon previous work done on the Clatsop Plains, we implemented a study to develop techniques to improve coastal prairie restoration in this region. The objective of this study was to identify an effective site preparation/treatment that resulted in the greatest success of seeded forb and graminoid establishment, while also limiting introduced graminoid and forb species. We examined the effectiveness of four treatments (untreated control, herbicide, soil inversion, and soil removal) at three sites on the Clatsop Plains. After three seasons, the soil removal treatment enhanced native species abundance while maintaining low cover of introduced forbs and graminoids. However, cost of these methods is also an important consideration for land managers. Soil removal was the most effective treatment we tested, but it would be more expensive to implement on a large scale compared to the other treatments.