I have some very old primes (grandfather's 1950s Exakta Varex lenses, ranging from 28mm to 85mm) that I've been really enjoying on my Sony NEX with an adapter. It's partially sentimental, but I've also gotten some great shots from them.
One of my favorites of the series is the 85mm, but it has quite a bit of dust on the inside, and the focus ring puts up a heck of a fight when it's moved. There are a couple specks of dust that are occasionally noticeable in my pictures, sometimes glaring.
It feels silly to pay for professional cleaning of lenses that are likely worth far less than the cleaning cost. I'm mechanically inclined; what are my chances of success disassembling and cleaning them myself? Is there a generic guide about lens cleaning that you have used with success (what to oil the aperture blades with, what cleaning products to use, etc.)?