There is a statute of limitations here, you need to find out what it is for your state, although Im sure that 4 yrs is plenty of time to be considered it abandoned stuff. I probably would have threw that crap away and I wouldnt have even said a word to her, honestly if you have gone 4 years without this stuff, its obviously not that important to you. But, she knows about it now, and she would try to do something if you just chunked it.
I would research the statute, and then write a letter stating she has 2 weeks, yes only 2 weeks, I mean come on its been there forever, have it notarized, and then send it certified mail to her address.
In the letter, I would state, as per statute blah, blah, blah, your personal property has been stored by us for _____ years, you have 2 weeks to pick up your personal property, if it is not picked up by ______ date, it will be disposed of. End of story.
Kim