"Buying clean scores" as you put it for that app is a copyright violation.

Use an iPad, get a clean area, and take pictures rather than use scans. Or buy an e-print version of the score, export it as a .PDF, then import it that way. Then you "own" it already.

(FYI: I use it to take pictures of the TMEA/TBA handouts too at convention. Very handy, and I don't carry around a ton of paper)