I wouldn't call it easy.
We build cop cars at our shop. (Install lights, sirens, radios, etc. etc.) The worst so far for jobs from heck is corner strobes on Ford Expeditions. The reflector is a greenish stuff that creates a static cling powder that smells like fiberglass resin, and it happens no matter how carefully the reflector is drilled. The crap permeates every cranny of the sealed housings. Forget compressed air. (We drill a 1" hole in the headlight reflectors to install a flashing strobe element)
What we do is make up a mix of Comet cleanser and water, and swish it around. (About 5% Comet) The abrasive Comet scrubbing particles won't scratch the chromed plastic reflector material, that only happens if the surface is rubbed directly, but it does knock loose dust/dirt. You'll need a couple of coffee cups worth in the housing.
Completely rinse the housing to remove the sudsy Comet mixture.
Now, rinse the housing out completely with DISTILLED water. You'll need quite a bit. It has to be DISTILLED or you will have water spots.
Then, use denatured alcohol. Do NOT use rubbing alcohol, it needs to be the stuff you clean paintbrushes with. Make sure it's alcohol, not turpentine etc., alcohol leaves no residue. You can buy it by the gallon, and about two coffee cups per housing works. (We do several cars or SUV's at once) Swish all around and dump it out. That will displace any water left, and what might be left won't spot if it's distilled water.
Rig up a vacuum cleaner to pull air for a while, about 2 hours to help speed up the process. Let it air dry a day or so after that to make sure.
Trust me, there's no way to hurry it up.