Most Piano rolls are sold for the song .Foe example I have Can’t help falling in love with you by Elvis Presley. Because it by Elvis you may find a buyer that wants it because of the song and the writer. What he or she will pay is another story. They are available in large numbers so getting $5 or $10 dollars for one id good. You can get more if it is something that someone wants very badly but it is hard to put a set price on each one. Condition of the roll is important. It should work and if mold will cause it to tear it will be worthless. Mold on just the outside box is not to big of a problem. You can in some cases remove it if it has not blended in to the paper with the information on it at the end of the box. Di not try to remove mold unless you know what you are doing. Never use bleach for mold ,ever,more of any liquid can spread mold. dry dusting mold is the safest way to get some off. The box does not in most case play a big part in the value but in some collectible Antiques the original box can add a big percentage to the overall price. A good way to control the smell of mold in lets say a Saxophone case or Guitar case is to vacuum it out and place a Bounce dryer sheet or two in the case to help with the smell /Don’t spray fabreez or things like that as it is adding moisture to it. It may work in some cases but the higher the value the bigger the risk. Thank You Steve Sassano American Musical Instruments.