If it was acetone, another few days may help if the darkness around the top tang is oil soaking, but what about the other spots where you normally would not find oil? Builder might want to dab some whiting on the dark areas and let the wood sit in the sun for a day. If there is oil in the wood, this should begin to draw it out. If the dark spots are not oil, try a little common household bleach and the sunshine treatment. Remember to neutralize the bleach before refinishing. If you want to get more aggressive with chemicals, you might try the bleach concoctions that hardwood floor refinishers use, containing oxalic acid and also requiring neutralizing.
