I agree with Dale, if it's a lubricant the blower motor makes sense. If it is water - check for plugged/split condensation lines [usually gets plugged at the end at the drain or in the tubing near the draft blower] or I've seen several various issues with humidifiers. Please note I've seen small water leaks destroy boards. The blower motor comes on and blows that moisture all around inside that cabinet and it will start shorting things out in a hurry. The anticipation of waiting for the board to dry out and see if it will continue to function is a killer.