Use oven cleaner,it will take it down to the wood and remove every thing,oil and finish even in the checkering. Let it set about 15 min then rince with water. If you have dents,let it dry after removeing the finish and take a wet wash cloth put it on the dent and take a hot iron over the dent on the cloth and it will pull the dents out. Then let dry and finish the wood the way you want it.