Commentary for Bava Batra 5:10

הסיטון – a business man that purchases a lot together, and then goes back and sells to storekeepers bit by bit (i.e., wholesale provision dealer).

The wholesaler must clean out his measures once every thirty days and the householder once every twelve months. Rabban Shimon ben Gamaliel says: “The rule is just the opposite.”
The shopkeeper must clean out his measures twice in the week and polish his weights once a week and clean out his scales after every weighing.
Mishnah ten deals with the proper maintenance of weights and measures to ensure that the purchaser does not receive less than he bought.
The Torah (Leviticus 19:35-36) forbids falsifying weights and commands a person to keep properly weighed and maintained weights and measures. Our mishnah is concerned with the proper maintenance of weights and measures. According to the anonymous opinion in section one, a wholesaler who uses his measures frequently must clean them out once every thirty days. This is to prevent the buildup on the sides of the containers which will reduce the amount purchased. A householder, who uses his measure less frequently, need clean them out only once a year. Rabban Shimon ben Gamaliel holds that the opposite is true. According to him the more frequently one uses the measures, the less buildup will accumulate. Therefore, a householder must clean them out once every thirty days and a wholesaler only once a year. A shopkeeper, who uses his weights frequently, must clean them out twice a week. In addition he must once a week polish his weights so that they don’t grow heavier and clean out his scales after every use so that they don’t accumulate buildup.

מקנח מדיותיו – for the wine and/or the oil hat became congealed in them and the measurement is lessened.

ובעל הבית – that doesn’t sell frequently like a wholesale provision dealer, cleanses them once a year.

פעמים בשבת – the storekeeper is not liable to drip three drops as the wholesale provision dealer and the owner as it remains in the utensil and cleaves to it.

וממחה – he cleanses the stones of his scales that he weighs on them a moist/liquid thing.

על כל משקל ומשקל – every time that he weighs something, he cleanses it/wipes it down.