bills and omni plants

I have been playing sims 3 for a few years now and all of a sudden started having this issue.  My sims' inventory has recently started accumulating these bills and omni plants.  I am unable to sell or move the items.  It appears that every time the sim receives a gift in the mailbox one of these bills or omni plants is also created in addition to the gift.  These only show in inventory once the item is retrieved from  the mailbox.  The mail box only shows the gift.  In reading through other threads it looks like this is an old issue, however, I could not find any fix or resolution.  Any suggestions would be very much appreciated.