Answer:
Preferably be an organic solvent but......
Explanation:
Chemistry has one law only. Like dissolves like. If a substance is polar like table salt or sugar, it will dissolve in polar solvent like water. If it is non-polar like oil, it will dissolve in a non-polar solvent like kerosene, hexane, petrol or diesel.
However, removing an oil spot from clothes (I assume), will require a more complex system. Clothes detergent which is chemically known as Sodium laurylsuphate (SLS) is used to remove oil and stains from cloths. SLS decreases water surface tension by decreasing hydrogen bonding within water which now can penetrate into cloth fibres. Since SLS is organic salt, it will dissolve oil spot which is now miscible in water and therefore removes it from the cloth.
