Here are some more photos of the acid preparation experiment I tried last month. I shouldn't say 'tried' - because this succeeded beautifully. The jaw took about 8 days of acid bathing to completely remove all of the nodule. It did take about 3 gallons of vinegar (3.2 or 3.5 % Acetic Acid, if I remember correctly), which made for a grand total of $6 - definitely worth it, especially considering that there aren't any tool marks now, and I didn't really have to lift a finger. All this took was checking it daily, and replacing the vinegar after each 'batch' had been used up, so to speak (can you tell I didn't do well in chemistry?).
In any event, I am extremely happy because many fossils from this locality occur in nodules, and they are all of this same sediment with calcitic cement. I'll be at this locality in three days, so hopefully this time I'll find a skull or something else really neat.
Photo of the finished specimen after 200 hours (8 days) of acid preparation.