Will my ships ever dispose of wares?

[LameFox]

I have a Fill Shortages fleet carrying the primary Terran wares around, but it's mostly just filled up with energy cells because I guess they are more readily available. However they're also the easiest to come by for all my station traders. If the Fill Shortages fleet can't get rid of these will they ever drop them and move on, like the AI do? Or should I just take e-cells away from them entirely to make them move more important wares?