Extent of heat exchangers air conditioning / cleaning?

I'm talking about the thing that passenger side is under the plastic board of the windscreen wipers and the air is cooling.
It seems that this thing is air side a bit dirty and almost no air leaves through.

The airflow from the nozzles is so minimal.
Can hardly blow out a candle.

Is there any way to clean this thing without disassembly?
Moist cleaning without expanding is sure to give a swimming wall in the footroom?

From the footspace I reached up through the flap and cleaned up as good as possible.

Does anyone have any photos of a build-up lying around so I can take a picture?
Or pictures of a butcher where you see it?

Pictures of the heat exchanger
Pictures of the hole where he was inside.

Thank you

Ruedi