This item is normally used to moisten stamps but it can also be re-purposed and used to activate veneer tape. It's cheap and it works. I started using one of these in my shop a few years ago. It's been through the wringer and it still works like a champ. You can pick one up at your local office supply center for $4 or get it here for a bit less.

Approximately 3" in diameter.

Three Tips from Joe

• Squeeze the polyurethane sponge under the faucet a few times to get it pre-loaded with water. Then place it in the plastic cup and fill it with water. To have the right amount of water in the cup, turn it upside-down and briefly press the center of the sponge with your index finger. This will squeeze out some of the water. The remaining water will be the perfect amount for wetting veneer tape.
   
  
• To prevent mold from forming, be sure to dry the sponge when you are finished using the moistener.
   
  
• The sponge sits deeper in the cup than what you see in the product picture ("shrink-flation" I guess). I put a 3/8" thick piece of plastic under the sponge so it sits a bit higher than the edge of the cup. This makes it easier to moisten longer pieces of veneer tape.