In the past I've taken mine off periodically, just to clean out the oil residue that builds up in them over time. I've used various cleaners, but have found the best results from a bottle of Castrol Super-Clean. (The purple stuff). It gets all of the oil residue out, and virtually anything else that might have decided to adhere itself inside.
Fill it half way with water, add half a bottle of the Super-Clean, and then fill the rest of the way, until it's visible in the inlet/outlet on both sides. Let sit for a few minutes after agitating it. Then stick high pressure water hose nozzle in the neck that the turbo outlet matches, and run the water through for a couple of minutes. Then repeat the whole process. Turn upside down and let drain and dry outside for awhile.
If you have access to compressed air, I would stick the air nozzle in the same neck opening, holding a rag over the additional space to give a semi-seal. Then run compressed air through for a minute or two, which will help dry it as well as get any remaining metal frags out. It's all worked like a charm for me in the past...