Hb Brush Cleaner is the right product to clean a stubborn brush. It is meant to protect and clean the bristles of your Kolinsky brush hair. The best way to clean is with the monomer. Whenever it does not clean enough then we recommended using HB Brush Cleaner. Never use Acetone to clean. 

MADE IN USA

Ingredients: Ethyl Acetate, Butyl Acetate, Isopropyl Alchol, MEK, Alcohol 

2 fl oz / 59 mL & 4 fl oz/ 118 mL