Annie, if you have any issues, would you come back here and mention it? I'm like the others above, I've stored pearls for years in clear ziplocks, or clear plano boxes (the see-through or translucent kind with small dividers, hardware-box-style). I've never had any problems with them. So if it turns out there's some agent that's hurtful, please do let us know!
(I do keep them in a room where there's never perfume, room deodorizers, etc).