The air conditioner/heat pump in our coach house is a Mitsubishi Mr. Slim split unit. We have always cleaned the filters but recently we learned there are other parts that also need cleaning.
Thanks to YouTube we learned how to open the louvers so we could clean the blower,
What it looked like in there after not having never been cleaned in the eight years since it was installed.
It was going to take more than just bushing the dirt from the blower to remove the buildup. But that is a story for another day.