Have you ever wondered what’s involved with identity-preserved grains with regards to cleaning equipment used? Here is a video from Iowa State University Extension showing how to clean a combine between crop changeovers. There are several phases to this process, from removing the head, to cleaning out the stone trap (by hand as well as using compressed air), to opening access doors to clean out the grain augers, to the cleaning shoes, to the axles, as well as the snout and grain platform and auger. This is all done after allowing the combine to run a minute to clear as much out as possible.
Keep in mind that this is just one piece of equipment in the process. It’s easy to see after watching the video why it may be very difficult to get 100% purity while using equipment that is used for commodity crops for an IP crop. Grain carts and other transport augers are also touched on as well as discussion about safety and documentation.