Today all of use ball pen but students and some people still use fountain pen. What this pen allows is the correction because the ink used in these fountain pens can be erased by ink removers.
This invention is one of my very old inventions when I was a class 7 student. I use to do lots of spelling mistakes due to which I needed a ink remover. So here’s that formula for you to discover and start making yourself your own ink remover. You can actually start a factory of it, no kidding since it’s so easy and cheap to make, soon you will be making huge profit

To start with let me tell you what you need:

1. Water
2. Common salt
3. 12v 1AH battery eliminator / charger (see here)
4. Pencil led
5. Thick copper wire
6. Beaker

So as you can see these are not very costly items, most probably you will be having all these items in your house. If you don’t have a beaker you can use any cup / mug which is either of plastic or glass (no metal).
So now let’s start the fun, fill about 100ml of water in beaker and add half teaspoonful of salt and mix it water well. Now take think copper wire of about 4cm in length. If you don’t have think copper wire then you can combine many thin wires to make a thick one. Connect this cooper wire to negative (-) terminal of battery charger and dip it water as shown in figure. Now take about same 4cm in length a normal pencil led (take it out from a pencil) and connect it to positive (+) terminal and dip it in water. Make sure both of these copper and led electrodes do not touch each other. Now switch on the battery charger. You will see some brisk effervescence and bubbles. Keep it going for few minutes until you notice a smell and the colour of water changes to pale yellow. As soon as you see the change in colour, switch off the current and take out the electrodes, your ink remover id ready now.

To test it, use your fountain pen, then put a small drop of ink remover to erase it J. For your ease, keep this liquid in small plastic bottle (use thoroughly washed eye drops empty bottles). This ink remover also works for some thumb pad inks etc. if you find it working for some other inks also, do tell it here in your comments.