Index Finger

• Get a rag damp with water, and moisten the tip of your index finger. Run your finger along the joint, adjusting the pressure on your finger to reduce or increase the size of the caulk bead. This method works well for water-based caulks.
  
  

Ice Cube

• If you don't want a lot of caulk on your fingers, you can run an ice cube along the caulk bead. The only drawback to the method is you can only work on small sections of caulking. For longer runs, the fingertip with a wet rag is more practical.
  
  

Plastic Spoon

• Silicone and polyurethane caulks tend to be stickier. For that reason, a smooth tool, such as a plastic spoon, will help produce a smooth caulk bead. Again you want to get the spoon damp with a rag, carry the rag with you as you go and work the bead to the desired size. Any time the caulk begins to stick to the spoon, simply redampen it.
  
  

Caulk Bead Tool

• Like the spoon, the bead tool is effective in not sticking to the caulk, which produces a smooth bead. You'll still need to wet the tool. Besides the smooth caulk bead, using a tool will prevent harmful chemicals from contacting your skin in excess.