I guess it depends on who's doing it. The second most effective treatment I've had for muscle spasms was accupuncture mixed with ART (active release therapy), it was the type of accupuncture that focuses more on stimulating the spasm to release it than based on meridians or chi flow. The best by far has been my physiotherapist who does some very painful massages, but it takes 5-10 minutes for him to work most of them out.
I have also found heat packs to be useful, I have a bag of seeds designed to be put in the microwave and it lasts for a while, anything really for that purpose would work. Wearing that for a couple hours each day has helped my shoulder and neck spasms relax, although not fully. I've found it nearly impossible to release spasms myself, there's definitely some technique to it.