Just picked up an old 28-105 lens for a backup/beater rig I am putting together. Lens seems OK, but is very sticky at 28. Sticky may be a kind phrase; I thought the zoom locked for a second. It loosens up a bit after some vigorous zooming, but goes back to sticky pretty quick. It is sticky/rubbing through the rest of the range, but that is tolerable.
Any suggestions on lubing this thing up? Or taking it apart to clean? Or anything? Or should I just use it as a 35-105? 
Thanks for any ideas!

