It's amazing how more dust blows out of the crevices each time you blast it. Water down the floor well to help keep down dust when spraying, pull the air hose around slowly to limit splashing and/or kicking up dust and run your compressor air through about 50 feet of galvanized pipe before it goes into the water trap. That cools the air down and lets the moisture precipitate out of the otherwise hot/warm compressed air.
I learned that on line. I've never captured one drop of water in my water trap since I added that set-up. Here's a few pictures. In between these two pictures, my 50 feet of galvanized pipe zig-zags up the wall allowing the water to drain back to each downpipe with a ball valve. It peaks in the middle of the lengths of pipe, and most of the water drains out of the compressor side.
Notice how the feed to the water trap and coiled rubber hose are mounted above the drain pipe and force the air to go up while allowing the water to go down.