כִּכְלוּב֙ מָ֣לֵא ע֔וֹף כֵּ֥ן בָּתֵּיהֶ֖ם מְלֵאִ֣ים מִרְמָ֑ה עַל־כֵּ֥ן גָּדְל֖וּ וַֽיַּעֲשִֽׁירוּ׃
As a cage is full of birds, So are their houses full of deceit; Therefore they are become great, and waxen rich;
Mishnah Kelim
A fishing net is susceptible to uncleanness on account of its bag. Nets, snares, bird-traps, slings and fishermen's skeins are susceptible to uncleanness. A fish-trap, a bird-basket and a bird-cage are not susceptible to uncleanness.