Can I reuse the Touch Board from my project?

The simple answer is yes, you can easily remove the touch board and either change the sounds on the SD card or change the code and then put it into a new project. 

The more complicated answer is, it depends how you have attached it to your project. 
if you have just used Electric Paint to connect to the electrodes along the top then just pull the Touch Board away to break the paint, then if you want to clean the board chip the paint off the electrode using a knife. You can also wash it off with water but its best to chip off as much paint as possible first, then gently wash and rub the electrodes under a tap, make sure the Touch Board is completely dry before powering it up again. You can also use a baby wipe if you are worried about getting it too wet. 

If you have soldered or screwed the Touch Board into your project then you will just have to remove the screws and solder.