Cleaning the Ionizing Electrode on a Junkers WRP 250-8KG: Sandpaper or Liquid?

Hello
I have a Junkers WRP 250-8KG (hydrobattery) [10 years]
Recently I noticed that he was having more and more trouble lighting the main burner. The auxiliary one lights up "immediately", while the main one waits for who knows what (the magneto fires).

I have already read that I should clean (it certainly won't hurt) the ionizing electrode. However, I don't know how/with what to clean it. Either with delicate sandpaper or maybe some liquid (of course after removing the electrode).
I wonder if sandpaper will destroy the electrode? Is it a uniform "wire" or is it coated with something, creating potential differences during heating, and intense rubbing with paper will destroy the coating?

Second thing: once I remove the electrode, maybe I would clean something else.

And here's another question: What steps should I take to "maintain the stove"? How and with what? (I skip vacuuming the interior without disassembling anything - it's natural)?

You can easily clean the ionization electrode with fine sandpaper. Also blow out the pilot burner, dust tends to collect there and hinders the proper operation of the burner. You can also check whether the exchanger is not contaminated with soot.

Thanks
I have one more question because I have conflicting information from the forum.
Should the fire from the pilot heat the "bend" of the electrode or the end of the electrode? (So far it has heated the bend, but maybe if I change it it will be better)
Or maybe the main burner would ignite faster if the electrode (bend) was placed parallel to the burner (then the whole thing would be on fire), or should it remain in the "T" position towards the burner.

Now I'm wondering that it must remain in "T" for the pilot because when the main burner is turned on, it is supposed to heat the electrode.

Aha: what is an "exchanger"?
(By the way I don't see it anywhere in the combustion chamber soot)

marek003 wrote:

...what is an "exchanger"?

Each region is a different name for the same thing....
The heater, primary exchanger for WRP -8KG looks like this:

"Our luck in the Lublin province" (at least in the center of Lublin) it is called a heater (although it probably depends on the language the specialist uses) but thanks for the explanation and photo (but it is probably mounted "upside down" than shown in the photo) . I will also clean it to be sure.

I cleaned the electrode and everything is great. The main burner turns on 1 to 2 seconds after igniting the pilot (probably a matter of water pressure).

But now I have one more question. It doesn't bother me that much, but maybe it's a flaw and it's worth fixing.

Namely: my pilot lights up "only" after three "strikes" of the magneto. This is how it's supposed to be (there's a "delay" time for the electronics before it checks everything), is there still an error somewhere?

And one more thing: Are there any "patents" to turn the stove on with even lower "starting" pressure than standard?
(I don't know, replacing some membrane with a more delicate one, "improving" the electronics, or something else).