It is the second set I have purchased.
I clean the filter approximately every 2 years and the first kit provided 4 cleanings.
For the 5th cleaning, I used whatever was left from the first one and of course started with the new one.
Mine is cylindrical so it requires about double the amount compared to the classic square ones.
Less than 20 euros for 10 years and we are going for another 10.

My objection is not with the cleaner but generally with the High Air Flow filters. I have had a K&N filter in my car for the past 12 years and recently discovered that it allows more particles to enter the engine compared to a regular paper filter.
Since I live in a dusty area, and the minimal increase in performance does not interest me (but I am very interested in the longevity of my engine), I have switched to paper filters for the foreseeable future.

I have the same KN air filter. I put it first in a bag with water and cleaning soap for 3+ hours, then I let it dry and apply the oil. Completely satisfied!

Perfect and both very easy cleaning removes the previous oil and leaves the filter like new and the passage of the oil again is very easy because it is in spray form.

I tried it on an intake KN. It does the job, it's just that the cleaner runs out faster than the lubricant

Air filter cleaning kit that includes cleaning spray and lubricating spray which, with proper use, restore the filter's function (i.e. as it was the day we bought it). It remains to be seen in practice.