Taking a Joker from a dead hand

A hand is dead. Can I still take a Joker from its exposures?

Question 1 of up to 2

Is the Joker in an exposure that was made before the mistake — not in the exposure or the Mah Jongg declaration that made the hand dead?

Read every possible ruling for this situation

Earlier exposures ok

Yes — earlier valid exposures stay in play

Standard rule
Yes. Exposures that were valid when they were made stay on top of the dead player’s rack, and any Joker in them can still be exchanged by the other players on their own turns, with the matching natural tile, for the rest of the hand. The dead player hands over the Joker just as they would have before. Also, if a hand is actually dead but nobody has declared it yet, its exposed Jokers remain available until someone does.
Why
A proper exposure was public information the moment it went up, and a later mistake does not erase what was already legitimately on the table.
Common house rules
Some groups freeze everything on a dead rack or return all of its exposures to the hand. That is simpler but not the standard, so agree before play.

If your table agreed on a house rule before the game, that rule wins.

Under review by instructors

Sources consulted: Mahj Life Rules Wiki, Article 38 (Exchanging Jokers from a Dead Hand); Mahj Life Rules Wiki, Article 180 (Exchanging Jokers from an Undeclared-Dead Hand); Tom Sloper, Mah-Jongg FAQ 19 (American rules): “Can I redeem a joker from a dead player's rack?” and “What if a player is dead, but nobody has said they were dead?”; AMJA, The Complete American Mah Jongg Rulebook, FAQ: what happens to exposures when a hand is declared dead; Mahjcon Mahjpedia ID65 (Exchanging Jokers from a Dead Hand)

Not available

No — that exposure goes back into the rack

Standard rule
No. The exposure that caused the dead hand — the incorrect group, or the tiles put up for a mistaken Mah Jongg — goes back into the sloped part of the dead player’s rack, Jokers included. Those Jokers are out of reach for the rest of the hand. Earlier exposures that were valid stay up, and their Jokers remain available.
Why
Tiles exposed by mistake were never a legitimate part of the table, so they return to where they came from rather than becoming a prize.
Common house rules
Some tables leave the offending exposure up and let its Jokers be exchanged. The standard returns it to the rack.

If your table agreed on a house rule before the game, that rule wins.

Under review by instructors

Sources consulted: Mahj Life Rules Wiki, Article 38 (Exchanging Jokers from a Dead Hand); Mahj Life Rules Wiki, Article 24 (Reasons to Disqualify Another Player — procedure after disqualification); Tom Sloper, Mah-Jongg FAQ 19 (American rules): “Can I redeem a joker from a dead player's rack?” and “You mentioned something about returning tiles to my rack?”; AMJA, The Complete American Mah Jongg Rulebook, FAQ: what happens to exposures when a hand is declared dead; Mahjcon Mahjpedia ID145 (Exposures and Tiles from a Dead Hand)

Concealed none

No — a concealed hand has no valid exposures

Standard rule
No Jokers are available from this hand. A concealed hand is never supposed to have exposures, so every group that was put up was invalid. All exposed tiles return to the sloped part of the rack, and nothing from that hand can be exchanged.
Why
A concealed hand has no legitimate exposures, so there is nothing valid left on the rack to exchange from.
Common house rules
None that we know of. This one is played the same way at nearly every table.

If your table agreed on a house rule before the game, that rule wins.

Under review by instructors

Sources consulted: Mahj Life Rules Wiki, Article 38 (Exchanging Jokers from a Dead Hand); Tom Sloper, Mah-Jongg FAQ 19 (American rules): “Can I redeem a joker from a dead player's rack?” (Exposed Concealed Hand); AMJA, The Complete American Mah Jongg Rulebook, FAQ: exposure while playing a Concealed Hand; Mahjcon Mahjpedia ID65 (Exchanging Jokers from a Dead Hand)

All rules