Wash and peel the potato skin (peeling is optional and depends on personal choice)
Fill enough water in a large pot and add alum powder in it and mix wel
With the the help of potato chips slicer start making chips.For the crisscross pattern you have to use the serrated potato slicer which I have shown in the picture.
To make crisscross pattern first you have to put peeled potato on the slicer and then slice a chip by applying slight pressure on it.
Then for the next chips slightly twist the potato and make the next slice .So keep twisting the direction of potato after every chips.
If you want to make plain chips then you can use any normal potato slicer or a sharp knife.
Keep soaking all the potato chips in the water filled bowl in which you have mixed alum for about an hour.
When you finished making all the chips then drain the water and wash the chips three times in fresh water so that all excess starch is removed and on your last rinse you will see the water will be clear unlike the prior washes where the water will have milky traces of starch.
Boil enough water in a big pan and add some salt (enough to make the water taste salty) and a pinch of alum powder.
When water starts to boil add the drained potatoes in it.
Keep stirring gently till the water starts boiling again (about 2-3 minutes)
Drain the blanched potato chips over a colander to drain all the water.
Spread hot chips on a muslin cloth in a single layer,avoid overlapping.
They will dry in about 2 days time or depending on the heat in the climate
When they become dry and crisp store in a air tight jar and use till they last.