How to get hardened acrylic paint out of a brush?

I usually soak it in hot/warm water for about 30 minutes and then just use a washcloth or something to try and get it out a little at a time and if that doesn't work I soak it in hot soapy water and try it that way. I think the soapy water would do better for you. It usually works for me. 

I hope this helps in some way. 

It represents ask goo