after the Vasoline has been on for a while, take your multi-meter.... one contact on the positive terminal, drag the other contact across the area where the vasoline is... you will see a voltage reading, because the normal slight venting of the battery will deposit some acid, which will adhere to the vasoline, creating a current path across the battery. This will accelerate standing discharge of the battery's state of charge. Better choice is to use a commercially available battery cleaner, with leak detector, followed by a commercially available battery protector spray......