A scalper apparatus configured to divide a flow of material between filtered and unfiltered streams. The scalper apparatus may include a housing with an upper opening, a primary lower opening for outputting the filtered stream, and a secondary lower opening for outputting the unfiltered stream. The scalper apparatus may include a grate extending across the interior of the housing such that any material leaving the interior through the primary lower opening must pass through the grate while any material unable to pass through the grate is caused to move through the secondary lower opening. The scalper assembly may include a brush assembly with at least one brush movable across the grate, and a carrier assembly configured to carry the at least one brush across substantially an entire top of the grate.