Basically metal tools used to rub out scar tissue/adhesion in the fascia
I'm experimenting on myself with a stainless steel large kitchen spoon, it has a long curved rounded handle so I can reach my traps.
I'll do it every few days or maybe only once a week, but I'll report any pros cons that I can notice.
I did have some restrictions in my R shoulder that did go away, soooo...

I did it on my forearms but no redness showed there.
I do have some little bumps or nodules along my tendons in my forearms maybe I'll have to read up on tendinitis/tendinosis again.
Or I'll ask chiro to check it out one of these times- but no pain from it- or not noticeable anyway, might be affecting my fine finger uses...
videos - more should show to the side of this one.
http://www.youtube.com/watch?v=aRM3-9sja-g
very much like Gua Sha. An ancient Chinese method that lay people use in China.