White film on black handle mac makeup brushes?

i soaked my makeup brushes in water and mild soap to clean them. they were in water and soap for about 30 min. when i took them out the handles now have a white film on the black handles. what is it and how can i take it off. i scrubed them with a sponge but it won't come off the brushes! any ideas?White film on black handle mac makeup brushes?
Oh yeah, it's that film that some plastics get. Try rubbing the handles with baby oil.... or rub the film with a substance harder than the plastic, like a coin. Try the edge of a nickel, because it doesn't have a bumpy edge.