When touched, it sends people to an alternate reality where they were never born, similar to Stern's story "The Greatest Gift", which inspired the movie It's a Wonderful Life. As Artie put it, it literally "sweeps your life away". Only the person affected will remember everything about their previous existence. Once 'bonded' to a person, it won't work for anyone else until it is touched again, which reverses the effects. It is kept in Warehouse 13's Aisle of Noel, where all Christmas artifacts are kept.
In "The Greatest Gift" Pete accidentally activated the brush while shelving Rudolph's Nose and was transported to a universe where he was never born. In this alternate universe, MacPherson was still a Warehouse agent, Artie was in prison, and Myka's father was dead. Pete was able to reverse the effects of the brush just before MacPherson destroyed it by throwing it into the Lehmann Fornax.