I personally never had much luck smoothing them out with alcohol, I may simply lack the "touch". It either does nothing or all comes off when I've tried it.

If it's a rifle you intend to use, I'd take it off as it is not a very durable finish. I use BLOicon after getting the cosmolineicon out of the stock which can be removed in a variety of ways, citristrip is my current favorite. It will also remove the shellac very easily.