Cov yeeb nkab dej tshwj xeeb no muab cov neeg siv lub tshuab pom hauv daim ntawv ntawm ob chav percolators.
Thaum nqus tau, cov pa luam yeeb yog lim thiab txias yog siv nrog cov dej khov-catcher.
Cov xim bold nyob rau sab saum toj ntawm lub qhov ncauj thiab ntawm lub hauv paus ntawm cov yeeb nkab ntxiv rau cov yeeb nkab qhov kev thov thiab kev nyiam.