Use paint thinner (i.e., mineral spirits) to clean the brush. The residue left behind is probably not water soluable.
After cleaning, blot out the excess thinner and allow to hang with the bristles pointing down. You may also form an aluminum "sheath" on the brush until it is completely dry. You should be able to use it just fine once the thinner has dried.
__________________
+++++++++++Boom!
|