I found this on the NH birds list and tried it out this morning after breakfast,
It worked. a very nice feeder tip. Here is what the woman had to say:

"Blue jays love to eat egg shells in the winter.I just crumble them and throw
them on the ground and the war begins.Apparently it's a source of calcium for
them. B Judy Flanders,Henniker "

Anyone have other feeder tip/experence to share?

Good birding
Peter Manship