We typically accumulate the books and school supplies for an average of 3-6 months (depending on the volume we receive) before we ship them out.  We ship them in drums / barrels like as you can see in this flickr album. We ship the drums of books / school supplies to Sierra Leone, Liberia, Cameroon and Tanzania.  Frequency varies by country.

We generally send them to a shipper / consolidator who forwards / delivers to the destination country.