Joe Viera in Toronto has cleaned and adjusted my 500 CM, 50mm, 80mm and 150mm lenses. I thought they were OK when I sent them in, wanted to confirm accurate shutter speeds etc. They came back better than new, both mechanically and aesthetically. The 50mm is 68 vintage and the 150 was a 1970 model, these came back smooth as silk and look like new, did not expect these old silver lenses to look this good.
Recommend Joe for any of your repair needs, he also has an inventory of equipment at reasonable prices.