Mistake #3: Thinking that glue is all that would be on top of the 100 year old floors.
Clearly, whoever lived there before us, and then before them, had good taste because under the awesome black tiles (and glue) there was, once again, another surprise. Painted wood! Not to mention the part of the floor where they had moved the radiator and left a gaping hole. Oh, how I would have liked to meet these people and their awesome decision making skills, or lack there of. So we do what any young couple would do who have no idea what to do, we wipe down the floor with Mineral Spirits* (and in the process get high off of the fumes). And wallah! we're finally starting to see the floors!
Clearly, we have low expectations at this point.
* I would not suggest doing this. It's very flammable but clearly, at this point, we didn't care. Blame it on the fatigue or the laziness. You take your pick.