Q: What is a makeup brush shield for?
A: Holding the bristles in shape while a brush dries, and protecting the head in a bag. Drying a brush without its shape held is what causes bristles to splay over time.
Q: How do you dry makeup brushes properly?
A: Reshape the head while damp, then dry flat with the bristles hanging over an edge. Drying upright lets water run into the ferrule, which loosens the glue holding the bristles.
Q: Can you use a brush shield on a wet brush?
A: Yes, that is when it is most useful. Slide it over the freshly washed head so the bristles set back into shape as they dry.