Gel pens are expensive and often stop working or never work at all. Is there a good way to revive gel pens that have lots of ink but refuse to write? I have tried heat, saliva, gravity, and the age old method of madly scribbling all over paper for a minute or two.
Usually, it is due to ink that gets dry and stuck at the tip, so the metal ball doesn't roll properly. Heat up the nib with fire (a lighter is the best way). Only heat the end, and not too much, it is just to make the stuck dry ink to "melt" a bit and allow the metal ball to roll again. If you heat much, you will roast the ink and it will get stuck forever.
Obvious way is keep shaking it and then scribbling on a page. If that doesn't work, try put the nib under a running water tap. Once you see the ink flowing, the pen should start working after letting it dry and further scribbling on a page.
Tip: When scribbling, use at least half of a scrap piece of paper and use long strides rather than short.
I have tried this and it worked for me.Gel pens have a long tube like structure commonly called the 'refill'.The tip of the tube is occupied by the nib.Many a times I have seen that the nib stops working as it gets easily damged.
This nib can be removed and only the plastic tube with ink is left.Note here,that the nib not just only mean the metallic part but also the plastic casing holding it.
Use nib of empty refill for replacement :- You can remove the nib of the non working gel pen you are talking about with your hands or by some sort of instruments by tilting it left and right and slowly pulling it up.It is better if you do it in a washbasin.Also remember to hold the tube horizontal,for the viscous ink wont flow away.Now take another empty refill,take out its nib in the same way and insert it in the desired refill.Before that,make sure to check the compatibility of the nib of this empty refill with the one you opened.
You can use alcohol as it is a good non polar solvent :- Alcohol is a good non polar solvent and you can easily dissolve ink in it.So, you can open the nib like I mentioned above,use a dropper and put 1-2 drops of alcohol on it from the tip where there is ink.Shake the refill after closing the nib.If the ink were clogged,it would flow smoothly now.