Hi everyone
I have this fantastic shower, but when the time passes it gets dirty. So how to clean it in depth?
Pulycuff and descaling are done, but how to get into that micro holes? I tried to blow with my mouth (sorry, I had no better ideas) sticked to the shower into the various parts and the airflow differed. And I can see that when looking at the shower during flushing. Only part of it buzzes with the water. Maybe while pulling a shot the pressure is higher enough, so the water flows also through the other part.... hmm. The coffee puck looks like well and even penetrated with water even when I crush it with my fingers.
Do you have any thoughts?
PS. sorry for my English.

Try using your steam wand instead of your mouth.

Are you removing the Matrix from the machine and soaking the screen in a hot Puly Caff solution?

My mouth helped me check the air flow only.

I'll try to clean the shower with steam wand.
I was soaking the matrix in the warm Puly Caff, but not hot. I'll try the boiling water.

The general problem is that the pressure is required to go through the shower. While using it, it is an advantage, but in cleaning it is problematic as you can't easely go through with the cleaning solution.

I'm afraid those tries will not help, but maybe the water flow gets even in higher pressures that take place while brewing.

I just wasn't sure if you were back flushing with Puly Caff or removing the screen to clean separately. I use Cafiza but I don't think the cleaner would make a difference.

Every few weeks I leave the shower screens and portafilter baskets to soak in detergent solution overnight. (Do not soak brass parts like portafilters or dispersion blocks for that long.)

Every few months I also clean the screens and baskets in detergent solution in an ultrasonic cleaning machine like the ones sold to clean jewelry and dental appliances. The machine's ultrasonic part is on for eight minutes and I start another cycle every hour or so during the evening. I leave everything soaking in solution overnight and then rinse in the morning with just water and a couple cycles.

Ultrasonic cleaning machine... Hmm... I feel it a bit like a stack overflow in my coffee setup.
Here you can see how it goes. I already ordered a new one.

Try to put the screen shower in a boiling water pot for 20-30 minutes, i mean let the water boils for 20-30 minutes with the screen shower in the pot, then switch off the heating source and add some cleaning powder, let soak for the night, the day after rinsing again in a boiling fresh water pot for few minutes, then install it.
Anyway with such screen shower i would recommend a frequent cleaning as suggested by others.
By the way i would provide even a bit of maintenance to the group head since he squeak a lot