How to save seeds from sweetcorn plant?

I have 7 out of the 30 or so seeds that I planted live, so I want to save a few cobs for seeds to plant next year en-mass. What's best way to prepare the seeds to ensure they will germinate ok?
Thanks J.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.