FOr the record, I have cleaned oily blades from a number of nikon pre-AI, Ai, and AIS lenses.
The problem with oily blades is that once the helical grease/oil breaksdown or starts travelling from the helical, just cleaning the blades does not solve the problem. The oil will just seep back into the blades. You have to dissasemble everything and clean the old lubricant off completely with a solvent. Then add fresh lubricant and reassemble.
It is possible that when your lens was serviced, they only cleaned the blades. But depending on the design of the lens, some will be more prone to problems like this anyway. Is the 35mm f2 a fairly compact lens?