Acetone is sure one way people do it and it is what Carbon Tech recomends. Than and isoproypel Alcohol...

Or you can use wraps as fletching sticks to that way better than arrow shaft...

Others just clean the shaft real good with warm soapy water to try to get all the grease and oil off of it... I have never had trouble with getting fletching to stick so I have never had to resort to this... Of course, I haven't fletched more than 3 dozen arrows either so my time will come, of that I am sure.