Like everyone else said, heat it. And don't be shy about it either. I used to think that putting the vial under running warm water in the sink would be enough, but now I heat the water separately until it's almost boiling and then put the vial into the water. That works much better. Just make sure the vial and contents are already warmed up. I don't know how heat sensitive standard vials are, but you don't want to risk cracking the vial due to rapid transition from cold to hot.