Nodov and Avihu died in the mishkan. This should have caused the mishkan to have become tomei. I heard that the Tur explained that the mishkan had a status of “kovua” and therefore did not become tomei.
Nevertheless, the contents of the mishkan would have become tomei. There are certain contents of the mishkan, most noticeably the Shulchan, which cannot be purified by immersion in a mikvah. (see the Bartenura on Mishna Chagiga 3 (8)).
What was done about the Shulchan which became tomei??