Hi Friends, had a similar problem with a Pentax "A" 35-105 mm f3.5 Lens - bought Like New for US $ 65 + Tax at Kaufman's Camera in the Bay Area CA. I reckoned a CLA would cost more than buying another one, say from KEH com - $ 149 then. I then took the DIY route after reading up some resources on the Internet and Pentax Forums worldwide. I decided on a rear entry as this was easier and less complex then entering the Lens from the front. I knew both sides should be cleaned to remove the gumming up of the blades, but reasoned the front facing side may just loosen up a bit too. I used lots of Johnson's Q-Tips dipped in WD-40 - gently and very little WD-40 at a time avoiding drips and fibres coming off from the Q-tips. A lot of brown gooey stuff came out till there was no more discoloration of the Q-tips. Put back the rear elements. Had a perfect working lens - checked and compared with a lot of test shots I had filed earlier. Regards and Good Luck. Bipin from Thornhill Ontario.