All snowboard bases have a layer of (p-tex) skin, with pores in it. Applying heat to the base opens up those pores to allow wax to be absorbed. Every season these pores get to small to allow this happen. this can be solved with a simple procedure. This should be completed about every half a season.
First the board must have no wax on the base. This will ruin the sandpaper. Using the plastic scraper and remove all wax. Base cleaner can also aid in removing the wax. Once that is done wet the sandpaper with some water and use a light pressure to sand the base. Use long strokes going for the nose(front of board) to the tail(rear of board). You will want to create a pattern on the base which will be invisble to the human eye. Just don't push to hard. Do this about 4-5 times across the surface of the base. If you have any doubt about what you are doing please take your board to a local board shop a pay them $20 to do it for you.
Now it is time to clean the base. using the base cleaner wet a rag or a paper towel and clean the base of the board. After your board is dried it is now preped to be waxed or repaired.