you should, let's say, make the ebb / pbb can be sold as zero credit, however, retain in the item list.

this way, people can remove their ebb without messing with the hq massively.
there were so many ebb, it is not enough even with 12 HQ expansion.
and the ship is huge (6 slot), so player need to move all item in the HQ around.
and we people even relog in to the old storage account to pump sailor out.

if you mark the ebb/pbb to be sold as zero credit while retain in item list, you solve everything :-)