A player in my game wishes to create a Molotov Cocktail - arguably, some alcohol in a bottle, with a piece of oiled cloth as fuse. Is that viable in a fantasy game, assuming technology of say the Renaissance period?

There are three components to this question, I think

1. Is it possible to gather the materials to create a Molotov Cocktail? Wikipedia says gasoline is used - will any type of flammable liquid works?
2. How likely is a character to know how to create one?
3. Is it easy to use in combat, and safe to carry around while adventuring (trekking long distances, climbing up sheer cliffs etc.)

**Update:** I am adding some setting info to provide context.

It's a homebrewed setting where it is high fantasy, pretty much like Eberron. There is also technology, such as clockwork and machinery, but the source of power is still rooted in elemental magic. For instance, instead of using engines using fuel or gasoline, the engines are ran by trapping elemental spirits within it, and the engine will then run clockworks, machinery and other contraptions. Was there discovery of petrol or gasoline? I would doubt so, because people rely on elemental magic for pretty much everything else.

In short, it's Eberron + Legend (Dragon Warriors' setting) + a mix of 'magi-tech'. That said, *I am also interested in answer for a culture or setting with technology equivalent to the Renaissance period.*, so that when I justify to the players, I have some ground as to my justifications instead of "because my setting notes say so".

**Update 2**: The system in question is 13th Age. However, there's no rules for such devices in the game.