In Bereishit ch 50 v 2 we read of Joseph embalming Yaakov:
"וַיְצַו יוֹסֵף אֶת־עֲבָדָיו אֶת־הָרֹפְאִים לַחֲנֹט אֶת־אָבִיו וַיַּחַנְטוּ הָרֹפְאִים אֶת־יִשְׂרָאֵל׃
Then Joseph ordered the physicians in his service to embalm his father, and the physicians embalmed Israel. "
Embalming is not practiced today. Is there an approach to embalming that Joseph could have used that would be Halachically permissible? This site talks about Halachically acceptable forms of embalming, but does not go into much detail:
As time goes on, and our knowledge of chemistry advances, other methods may be developed which Jewish law may consider legitimate.
Perhaps there was a Halachically acceptable approach to embalming that was used by Joseph. If so, what might it have entailed?
Addendum: When searching the web using some of the information in the answer below, I ran across this site which asks, "Was Joseph Punished for Embalming Yakov's Body?"