Have you been using your Wacom Tablets alot? and wanting to replace your Nibs? We I have found Nib Replacements to refill those worn out nibs. All compatible to your Intous 4,Intouse3 and Bamboo Fun.
For Wacom Bamboo CTL460, CTH460, CTH461, CTH661
INTUOS3 Grip Pen and Nib Set (Black and White) with Accessory Kit
For Intous4 Pen Grip, Nib set (Black and White)