DH bought me a nice set of brushes for Christmas. Amagic I think they say. I have soaked and washed them at least 6-8 times but when they dry they are hard as they were originally. So hard I'm afraid to force with my fingers as I don't want to harm them. They are acrylic/nylon or some similar material. Yesterday I soaked them in Dawn solution over night and today cleaned them in my palm as I was taught in high school 40 years ago. I spent 30 minutes at least, swishing and rinsing. I checked this evening and they are starting to harden up again as they're 75% dry now. I'm very new to oils so I've not done something right. Tell me what it is?