What happens after the cow is slaughtered, tripe is made from cow stomachs, I am now sure which one. But if this is standard there must be lots of the pseudo-be

What happens after the cow is slaughtered, tripe is made from cow stomachs, I am now sure which one. But if this is standard there must be lots of the pseudo-bezoars. Are they cleaned up, dissolved in acid, have the accumulated lots of bits of wire and nails? Mention was made of processing silage, ferrous objects could be removed at that stage.