When dough remains in the grooves of a kneading trough, if there is as much as an olive's [volume] in one place, he must remove [it]; but if not, it is null because of its insignificance. And likewise regarding the [laws of] contamination. If he objects to it, it interposes; but if he desires it to remain, then it is as the trough.  [Regarding] “deaf” dough, if there is [dough] similar to it that has already leavened, it is forbidden.