Self-targeting Morale Boost items cannot be used if you already have maximum Morale of +10%. Self-targeting Death Penalty removal items cannot be used if you have no Death Penalty. This principle also applies to party-targeting items when every member in your party has maximum Morale or no Death Penalty, respectively.
With the exception of Powerstone of Courage, Morale Boosts gained through these items do not cause skills to instantly recharge.
Elixir of Valor is the only one of these items that can be sold to merchants, with a value of 100.