וְאֶת־הַבַּ֛יִת יַקְצִ֥עַ מִבַּ֖יִת סָבִ֑יב וְשָׁפְכ֗וּ אֶת־הֶֽעָפָר֙ אֲשֶׁ֣ר הִקְצ֔וּ אֶל־מִח֣וּץ לָעִ֔יר אֶל־מָק֖וֹם טָמֵֽא׃
And he shall cause the house to be scraped within round about, and they shall pour out the mortar that they scrape off without the city into an unclean place.
Rashi on Leviticus
יקצע — rogner in old French, SCRAPE OFF, and in Mishnaic Hebrew it occurs many times.
Rashbam on Leviticus
יקציע, peels. Either as in Isaiah 44,13 “with a scraping tool,” or as suggested by the Talmud that the walls will be peeled off to the depth of a handbreadth. (Keylim 27,4).
Siftei Chakhamim
From within. מבית does not mean “from the house,” because it is missing the ה (מהבית). Also, it would not be understandable to say that he should scrape the house from the house.