you can't make a silk purse out of a sow's ear 巧婦難為無米之炊

You can't make a silk purse out of a sow's ear.  (old-fashioned)

something that you say which means you cannot make a good quality product using bad quality materials To make chairs that'll last, you need good strong pieces of wood. You can't make a silk purse out of a sow's ear.