How to fix pens with ink that is too thick?

[amperomierz]

I found over 20 pens in the trash with full ink cartridges but it's hard to write in them and every now and then they stop writing and I have to blow them out but they write a few words or a few sentences and it's the same and that's why it's like this that normal ink has the hardness of water and the ink from these pens has the hardness of jelly. Is there any way to make this ink more water-based? Injecting water with a syringe even through a needle will not mix the water with the inks and I tried to do the same but even if by some miracle it worked, if this ink was diluted it could have a weaker color and it could be difficult to read what I wrote with these pens. Most often the ink becomes too hard when pens lie unused for years. Once I found pens in the attic, the ink was as hard as a rock, so I threw them out immediately, but in such extreme cases, when the ink is as hard as a rock, can such refills be repaired to make the ink as hard as a rock if I found such pens? When it is difficult to move the pen across the paper while writing, is it the fault of the ink being too hard or the fault of the construction of the refill tip?

 

[rgd1101]

that the pen? there are some use gel ink

 

[amperomierz]

All the pens found in the trash are identical and they all look exactly like the ones in this picture.