Are jokers in a “dead” hand available to exchange?

The answer to this is that it depends. You may exchange jokers from any exposures that were made before the hand was declared “dead.” Any jokers in the exposure that actually made the hand dead are not available for exchange. These jokers, along with the rest of the exposure that made the hand dead should be returned to the sloped part of the player’s rack. The only exposures remaining on top of the player's rack should be those made prior to the hand being declared dead. However, if the hand was not declared dead until later in the game, all exposed jokers would be available for exchange.

There's one more thing to consider... If a player's hand is called dead because their exposures indicate that they are playing a concealed hand, then all exposures are returned to the sloped part of the player's rack, and no jokers are available for exchange.