Peeled of Potato and slice it thin but not too thin. Around 2 mm is fine.

Soak this slices in water with alum for 5-6 hrs. Wash it so all alum will get washed out.

Now boil water in deep and large pot. Make sure potato will get enough space to float. Add salt. Add first 250 gms taste water. It should be salty but not over salty.

Add 1/4 potato slices in it. Get it cook 2/3 percent or al dente. Take slices out of water. And immediately arrange each slice on cotton spread sheet. Repeat this for all remaining slices. Sun dry it for 2-3 days or it gets hard and little translucent.

Fry chips as per your need. This chips can be store for more than year. Just store it in air tight packaging.