It's also worth pointing out that non-trivial numbers of people habitually cleaned their glasses by using the (clean) pad of their thumb. Assuming the skin is completely clean and dry, this is actually fairly effective, though I can't think that many people would do it if they had a microfibre cloth to hand.

At one time, however, this method of cleaning glasses appears to have been fairly popular. It can be seen in various films and movies from the 1950s and 1960s, that is, before microfibre cloth came into being. The only example I can think of right now occurs in the first episode of Monty Python's Flying Circus (1969), in which a soldier (Terry Jones), struggling to read a sign at distance, takes off his glasses and rubs one of the lenses with his thumb, all with one hand. The gesture is carried out nonchalantly, implying habit, and as I say, it can be seen often enough in other films and shows of the period.

Based on my limited knowledge of domestic history I believe it would be soap, water and linen or soft paper, may vary depending on the time period as these items (soap specially) varied greatly in form and availability throughout history You may be interested in looking at how people cleaned glass items in general for a good reference as well