Leviticus 10:5

בכתנתם IN THEIR GARMENTS — in those of the dead (not in their own garments). This tells us that their garments had not been destroyed by fire, but their souls alone (neither their clothing nor bodies showed signs of burning; they had been struck by fire inwardly): there entered into their nostrils something like two threads of fire which burnt them to death (Sifra, Shemini, Mechilta d'Miluim 2 34; Sanhedrin 52a).

וַֽיִּקְרְב֗וּ וַיִּשָּׂאֻם֙ בְּכֻתֳּנֹתָ֔ם אֶל־מִח֖וּץ לַֽמַּחֲנֶ֑ה כַּאֲשֶׁ֖ר דִּבֶּ֥ר מֹשֶֽׁה׃

So they went near, and carried them in their coats out of the camp; as Moshe had said.