Do not worry that there are no spoilers, although if you have arrived here, it is that you are in the last episode of one of the revelation series of the moment: Little Orthodox (Unorthodox).
Why do Orthodox Jews cover the kitchen with silver foil to celebrate Passach?
We have consulted different sources in this regard and it seems to be due to a comment made by Ben Gurion (who gives his name to the main Tel Aviv airport for being the prime minister of Israel during the years 1948-1954).
The comment, referring to purity during the Passover (celebration of the departure of the Jewish people from Egypt, with Moses in the lead) alluded to the fact that the United States is not the place where there is less purity to celebrate the holiday in the synagogues, but in homes and in particular in kitchens, where non-kosher products have been cooked and handled for the rest of the year. So with the silver paper a new surface is given to the entire kitchen (faucets included) to elevate it to a new condition during the celebration.
This preparation also affects cleaning the house in depth to remove all possible traces of impure food.
The tradition of covering the kitchen is not exclusive to the Hasidic Jews on which the Netflix series focuses