Has anyone found a technique to overcome blocking?

Has anyone found a technique to overcome blocking? Over the last 20 years I've worked really hard to beat my stuttering. I almost have it beat; most people don't even realize I stutter, but I can't stop blocking. It's like I'll be talking fine-going right along and then BAM!, I can't even start the word. None of the speech therapists have ever given me anything useful to use. Most therapists say it's emotional and try to tell me to calm down. I know this isn't right because even when I'm perfectly calm, confident, and happy I still block. Has anyone had any success overcoming blocking?