In a glass case at the Eretz Museum in Tel Aviv was a collection of ancient oil lamps.
Olive oil was placed into the clam shell shaped lamps found in the ruins of towns from the times of early Israel before the exile to Babylon.  The pinched fronts held wicks of linen or other fiber.  The educated read at night. 

This is a photo of a replica of a Roman/Byzantine era olive oil lamp that I purchased in Jerusalem during 2002.  The replica was of porous earthenware, yet it burned brightly for hours with a little olive oil.  The oil gradually leaked through the terra cotta, thus it was an inefficient replica.  Lamps for sale in an antiquities shop and described as genuine appeared to be of finer grained ceramics.