I take the gun to the sink and with the flexible spray thingy, turn the gun/glass so gravity will have the water run down out of the lens into the sink, and spray up against the lens. All scopes are sealed for submersion so the water has no adverse effect, no different than a rainstorm. The water lubricates the glass surface so grit will slide across without scratching and gravity takes any/all grit out safely. Every nook and cranny is flushed clean looking like a right out of the box scope. You just have a few remaining droplets to dry off just like raindrops. Then if you have something like an oil smear you can clean it with lens cleaner without fear of picking up some tiny speck of grit stuck around the edge of the lens and scratching it as you wipe.
Regarding using any sort of compressed air other than a manually operated bulb, anyone that works with precision glass will tell you to never use compressed air. Any hard object, sand, grit becomes a high speed projectile, on a larger scale it is called sandblasting. Do it enough times and you will see tiny chip marks.
Stand up and be counted, join an outdoor sports organization
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