No. But I always prefer to clean them. You see, the cap goo is conductive and it could cause a short. In fact, some boards dont work then after cleaning do. That may be due to multiple shorts on the board. Still means they need a re-cap even if they work after cleaning. You can generally look at the caps and see if they are leaking bad or not. Also it seems hit or miss. Some boards I have show zero signs of leaking while another machine of the same model is toast.