I am posting this for Marsha - Her message is not getting through.
I bought a painting box from AIRFLOAT which has foam liners to fit
various sized frames. The painting fits inside the liner. I seal with
packing tape. I have sent paintings to juried national shows this way
ONLY I include a pre-paid return label in an envelope pasted to the
inside lid of the box. I send them UPS which takes a larger size and
more pounds. I have used the Airfloat box over and over again. It is a
little pricey though. I also use plexiglas instead of glass on the
paintings. Hope this helps.