I haven't been using cartos long enough to have cleaned one yet, but I agree on watching out for oils and stuff from a compressor. I'm saving my cartos up and going to try PBusardo's method to clean them when I have 8 or 10 to work with.
Link is here. Don't know if it will work for me, but that's the plan.
Off topic, I've spent the past hour or so cleaning a few stardusts, a couple of eGo-C atties, filling stuff and generally tidying up my vape gear. Was just thinking I might post about cleaning gear, checked in here and saw your post Ravage. You beat me to it

and with a good question too!
Back on topic, lot's of good suggestions here. Hope things work out for you.