You know that moment, when you spot a dust particle on the sensor while changing the lens? Here's a tip. Don't try to blow it. You might spit on the very center of the sensor.
And spit is no good. It leaves a huge spot on every single photo you take, and you'll spend twice the time in post processing trying to get rid of the spot.
I bought a sensor cleaning kit and it came today. Of course - the brush is too big for E-M5 little sensor. So it got complicated. I felt like a surgeon. The patient lived. It does take photos with no spots in the middle. Not sure yet if I didn't break the in-body image stabilisation. It'll turn out in the upcoming days.