We do seal them as good as we can, and use desiccant packets inside the panels. Most of them are in places where they can't be made removable though, and that would be another nightmare at this plant...
What we really need is an IP69k touchscreen, but none exist that I could find, except for a few custom ones that are used on our metal detectors.
We have a pretty sharp guy managing the sanitation crew right now, but he is likely to get promoted...and the hose monkeys are not easily trained and have a high turnover rate...
At my previous job in the tire industry, we used conformal coated PanelMates with great success resisting dust, so I thought it would be worth trying here to battle the corrosive atmosphere and moisture. Plus, since most of our HMIs are Panelview Plus and Standard, the migration would be less painful to stick with a/b products.
We are also considering Red Lion, but I had some problems with C3 (I bricked a G303K)...so that did not help the likelihood that we'd go that route, and I have no evidence they'd survive any better than the rockwell stuff...