<<Disclaimer: Verify this information before applying it to your situation.>>

The reason that it is easy to remove wheat from corn is due to the relatively
large difference in kernal size between wheat and corn.  you can not see any
contamination of any kind in the product stream as it is flowing.

The problem in oats being contaminated with wheat is that the kernals are of
a very simmilar size. they can be seperated, but the equipment is not cheap
and requires quite a bit of  upkeep. crop rotation is a minor factor in cross
contamination.

Steve HOT and HUMID in S. FLA