Machshirin 2:3 - 2:4

ברזל טמא – that came from shards of impure vessels.

שבללו (that one smelted) – that one planed/scraped and combined with pure iron that comes from the wrought metal/polished block (see also Tractate Kelim, Chapter 11, Mishnah 1),

אם רוב מן הטמא טמא – the Sages decreed on metal vessels that were defiled and broken and were melted and made of them vessels that would return to their former defilement until he would sprinkle [water] upon them on the third and seventh [days] and immerse them and their sunset would come.

גסאריות (pots) – like a kind of pots that were made to urinate in them. And in the Arabic language we call them BISRIASH.

שישראל ונכרי מטילים לתוכן – urinate into them. And the urine of a heathen is ritually impure, for they (i.e., the Sages) decreed that they would be like those with a flux/gonorrhea for all their matters.

מי שפיכות (water that is poured out, dirty water) – water that they washed with and they pour them - outside, and they are under the presumption of being ritually impure.

אימתי- are dirty waters/waters that are poured out voided in a majority [of rain water].

בזמן שקדמו – that they (i.e., the dirty waters, water that is poured out) [came first] and afterwards the rainwater increased [as a majority] and purified them.

אבל אם קדמו מי גשמים – even if a bit of rain water fell upon them, they are impure.

המטהר את גגו (if one scrubs his roof) – We have the reading "המטהר את גגו" /if one purifies his roof. But there are those who have the reading, "הטורף את גגו"/if one scrubs his roof, meaning that he plasters his roof with plaster or lime to even it out. And the water that one places upon it when one purifies it or when one merely plastered it, they pour it (i.e., the water) and they purify itr, and similarly the water that one washes with them his clothing.

וירדו עליהן גשמין – which are pure waters. And the roof or the clothing drips water.

אם רוב מן הטהור טהור – as for example, if it would drip thin drops at the outset and afterwards it would drip thick drops, it is sure that the majority [of the water] is from the pure [water].

אם הוספיו לנטף – that the drops hurry to descend one after another more than at the outset, it is pure, for they certainly are the majority, and even if the drops themselves are larger from what they were at the beginning. But the Halakha is not according to Rabbi Yehuda.