Stuck in LASH (Paul O'Brian, 2000)

I’m playing through LASH out of curiosity, and I’ve gotten stuck while looting salvaging.

[spoiler]I am carrying:
a diamond ring
three marbles:
a brown marble
a blue marble
a swirl marble
a dirty bottle (which is empty)
a small book
a length of corroded wire
a silver harmonica
a white gold bracelet
a leather jacket
a pile of bones
a bellows
a battered case (which is closed)
a broken ceramic jar
a shovel

I’m not sure what to do now: I feel like the scraps of paper in the barn have to be useful, and I know how to play the harmonica, but not what notes to play. The obvious puzzles to solve now are the safe and the steel vault door, and I know what data I need for the latter, but I don’t know where to find it.[/spoiler]