Potions identification can be usually made by tasting a bit of a potion and the drinker can fully know the properties of the potion. However it's not rational to be able to tell the properties of a non-edible potion like "Oil of Sharpness" that is supposed to be applied on a weapon in order to work.
So I'm asking, how is one supposed to quickly understand the properties of said type of potion? I know that maintaining focus in a short rest is a possible way to find the properties, but trying to see if anyone else has a quicker way of identification similar to that of tasting a potion.