the best stuff i ever used was citrus based bicycle chain degreaser (Pedro's i think? any other brand will do, as long as citrus based & get it in liquid form not spray). only a tiny dab is need and since its not harsh it works on the board, your clothes, skin, sails etc. bonus is that you come out smelling like oranges

any bike shop should have some.
rest is of course kerosene, wd40, gasoline (ugh).
the old manamana in bintan used to have a huge drum of degreasing fish oil for this purpose, environmentally friendly but smells awful (board smells like belachan after use).
sukhdev