After my Epson WorkForce WF-3620 became essentially unusable, I looked for explanations, since this would be the third printer I bought which got badly defective in 2½ years. One plausible explanation was that the printer head was clogged, even though I had tried automatic printer head cleaning. The prospect of searching for a new printer model, setting up a new printer and scrapping the old printer with its partially filled cartridges once more making me sick, I decided to try manual printer head cleaning.
The only way to do that which looked reasonably easy was to buy a cleaning kit. And unfortunately, the only way to get one for my printer model seemed to be to buy 118Ink.com's Printer Refresh Epson Blocked Printer Head Cleaning Kit, for £10, even though I am in Canada, which means paying a total £20 (36 CAD) to cover shipping. Even though 118ink features a big logo which pretends that delivery is free. My sickness convinced me to buy the kit anyway.
2-3 weeks later, the package arrived and I tried it. The first deception was that the kit shipped is not the one advertised. The syringe is different, the bottle is different (in fact, you get 2 small bottles), the gloves are different, even the instruction manual is different. The gloves are not large - it took some time to put them on without breaking them, even if my hands are not large. And unexpectedly, most importantly, the blotting paper is different - it's not pages of paper, but 2 or 4 strips. As 118Ink.com recommends 2 strips per cleaning, that means barely enough to clean 1 or 2 printer heads once, even though 118Ink.com also recommends cleaning all printer heads when you clean one. So the kit doesn't even provide enough blotting paper to clean 1 printer once!
Even though I only had problems with the black cartridge, I followed their recommendation and cleaned all cartridges. I did not expect the journey would be so complicated, so I did not fully document what I did from the start, and I can't remember everything I did, but I must have cleaned each head 2 or 3 times.
Initially, only the black cartridge was problematic. At a later point, magenta remained perfect. Yellow was good, others were worthless. Later that day, black and cyan were close to perfection, but magenta was worthless, and there was no yellow left at all. The day after, magenta and yellow improved a bit. After 3 automatic cleaning cycles, black was very close to perfection still, but all colors had become worthless. After 2 more cleaning cycles, yellow and magenta got perfect, cyan was as close to perfection as possible, but black had gotten worthless. 2 days later, black was back to near-perfection, but all colors had become basically worthless. 3 days later, after the black, cyan and magenta cartridges had been replaced, cyan was good, magenta was bad, and yellow and black had gotten worthless. After 1 automated cleaning of all cartridges, the situation remained unchanged. After 1 more automatic cleaning of the black cartridge, the situation was mostly unchanged, but black got half-OK. After 1 more automatic cleaning of the color cartridges, the situation was mostly unchanged, but magenta got good. After 1 more automatic cleaning of the black cartridge, the situation was mostly unchanged, but black got nearly perfect. After replacing the yellow cartridge, the situation was still black near-perfect, cyan almost perfect, magenta good, no yellow at all, so we seemed pretty close to the target. I then manual cleaned the yellow cartridge. In the next test, yellow was still worthless, but magenta had gotten closer to cyan than magenta (!), and black had degraded a bit. After 1 automatic cleaning of the color cartridges, the situation was unchanged, but magenta has degraded.
So, after all of this (and much more which I did not document), my black cartridge was printing OK, the yellow cartridge was not printing at all, the magenta cartridge was not printing magenta and the cyan cartridge was printing OK. And then, when we tried to actually print monochrome, there was no ink left after a few lines. And the printer started failing with the helpful error code 0x97 (actually, it started doing that a few days before, while I was trying to clean). The screen said to look at the manual or the website for more details. The manual obviously doesn't say a word about any error code, and Epson's website apparently doesn't even mention that error neither. Bravo, Epson. I found one source which claimed 0x97 was a symptom with many possible causes, one being clogged printer nozzles. But oddly enough, even though black seemed to be completely clogged initially, printing didn't trigger that error.
After I ran out of blotting paper, I tried using regular sheets of paper. That doesn't work well at all. You should rather follow 118Ink's suggestion to use kitchen roll.
During all of these cleaning attempts, we had to change all cartridges. Because as soon as 1 cartridge is considered empty, the printer simply refuses to print. It doesn't matter if what you print uses the empty cartridge or not, you just have to replace the cartridge. And automatic cleaning uses lots of ink! So we started with some levels of ink, and despite all these replacements, we ended with approximately the same levels of ink.
At that point, I was forced to conclude I had failed. I had started with a printer which "only" had problems printing monochrome, and after paying 30 CAD for a kit which I waited for weeks, replacing all cartridges with original Epson cartridges, manually cleaning each printhead several times, letting the fluid in some heads for hours, and at least 10 automatic cleaning cycles, I was left with an even less usable printer.
The steps I tried clearly had an effect. Just not the effect I was looking for. Overall, the situation seems to "evolve" approximately randomly. Either:
Ignore 118Ink's marketing. 118Ink does charge for shipping. And despite the "90 DAY MONEY BACK GUARANTEE", 118Ink requires notification within 7 days of receiving items.
If your WF-3620 is in a situation similar to mine, and if you're not looking forward to an investment which will require more work than replacing your printer, over a longer period of time than replacing your printer, which will cost you more than replacing your printer, and end up with a printer which prints even less, having to scrap not only the printer but a cleaning kit somewhat specific to that printer, then, rather than buying 118Ink.com's Epson Blocked Printer Head Cleaning Kit, just replace your printer. That advice is probably true for other Epson printers too.
If you try using the kit anyway, you'll notice that the liquid bottle will float in the hot water container. I suggest you attach something heavy to it to stabilize it.
Update 2020-01-22: A comment below suggest an "ink flush" would help. I have no idea if the WF-3620 has such a feature.