I've been having a problem with my ventilation for a long time.
If it's extremely warm outside, a muffin stiff comes to me from my ventilation.
I've already renewed the pollen filters.
When I was happy, I was sold a spray can, which I had to spray into all the ventilation grids.Then a white foam develops which supposedly kills all the bacteria in the ventilation system, because according to Audi it is supposed to be bacteria that should lie on the evaporator, which is supposed to be normal with air conditioning systems.
The Sprey then also held two weeks until the stench came back

Then I made the thick one happy again and had the ventilation cleaned again with such an ultrasonic evaporation device.
But it only lasted three weeks.
Now I am at the end with my Latin and hope that you can help me further.
Greeting Mark