Shawn,
There are several places that offer injector cleaning and flow testing services in the Toronto area. I had mine done in Oshawa, which I know is a little far for you in Hamilton (about 1.5 hours).
Be prepared to spend $20-$25 per injector, x6. This price may or may not include new o-rings and filter caps.
Why are you having them cleaned? I though you were selling?