I wouldn't use my wet/dry vac to clean the top of my Crossfire - a good lint roller does an excellent job, is quick and easy, and doesn't harm the top at all.

If the top does become soiled you should use something like RaggTopp cleaner or Meguiar's Canvas Cleaner and proceed lightly with a very soft brush. After the top dries fully follow up with Ragg Topp or Meguiar's Canvas Protectant.

I use the Meguiar's products and have even been able to remove tree sap from my roof with just a spray of plain water and a microfiber towel.