I think magenta_majors has it right: Have a master cleaning schedule and follow it. Regular inspections will tell you if your frequencies need to be adjusted. I, too, work in a dry enviroment - no washdown -- and we have been able to nearly eradicate stored pest issues (indian meal moth) by researching pest behaviors, then getting really serious about looking for webbing and other signs for activity to tell us where to step up our cleaning.
We, however, don't have to worry too much about pests coming in with our raw materials. If you think that is a source, find out what your suppliers are doing to ensure clean deliveries to you (and if your grains are coming from some pre-processor, it's possible they can be a resource for you on proper equipment cleaning).
Lastly, I would recommend creating some type of activity spreadsheet or database so you can track the type of pest and the locations. This will really help you pinpoint areas to work on.