Old world knowledge rocks.
Like when my friend who was born in Russia tells me to use a cap full of vinegar as laundry softener. “It’s disinfectant too, so it kills the bacteria that eats sweat and causes that body odor smell”. Thanks. Or, to put news paper over the spot on your carpet where you’ve spilled wax and then run a hot iron over it. The wax get absorbed into the paper.
Another old world knowledge idea is that if there are many remedies for something, than really, there are none. Because if there was a particular solution that worked amazingly well, no one would use the other solutions and they would have no reason to exist. This was read in an old short story by Chekhov.