diff --git a/include/cantera/equil/vcs_solve.h b/include/cantera/equil/vcs_solve.h
index 86046971b..eed8e91e2 100644
--- a/include/cantera/equil/vcs_solve.h
+++ b/include/cantera/equil/vcs_solve.h
@@ -419,6 +419,7 @@ public:
      * @param stateCalc Determines where to get the mole numbers from.
      *             -  VCS_STATECALC_OLD -> from m_molNumSpecies_old
      *             -  VCS_STATECALC_NEW -> from m_molNumSpecies_new
+     * @deprecated Unused. To be removed after Cantera 2.3.
      */
     void vcs_printSpeciesChemPot(const int stateCalc) const;
 
@@ -454,6 +455,7 @@ public:
      * work in species that are zeroed by element constraints.
      *
      * @returns the number of problems that must be checked.
+     * @deprecated Unused. To be removed after Cantera 2.3.
      */
     int vcs_phasePopDeterminePossibleList();
 
@@ -1268,6 +1270,7 @@ private:
     double l2normdg(double dg[]) const;
 
     //! Print out and check the elemental abundance vector
+    //! @deprecated Unused. To be removed after Cantera 2.3.
     void prneav() const;
 
     void checkDelta1(double* const ds, double* const delTPhMoles, size_t kspec);
diff --git a/src/equil/vcs_phaseStability.cpp b/src/equil/vcs_phaseStability.cpp
index c33ac7ff9..d784a1a94 100644
--- a/src/equil/vcs_phaseStability.cpp
+++ b/src/equil/vcs_phaseStability.cpp
@@ -104,6 +104,8 @@ bool VCS_SOLVE::vcs_popPhasePossible(const size_t iphasePop) const
 
 int VCS_SOLVE::vcs_phasePopDeterminePossibleList()
 {
+    warn_deprecated("VCS_SOLVE::vcs_phasePopDeterminePossibleList",
+                    "Unused. To be removed after Cantera 2.3.");
     int nfound = 0;
     phasePopProblemLists_.clear();
 
diff --git a/src/equil/vcs_solve_TP.cpp b/src/equil/vcs_solve_TP.cpp
index a5c55511e..92d791bfe 100644
--- a/src/equil/vcs_solve_TP.cpp
+++ b/src/equil/vcs_solve_TP.cpp
@@ -3092,6 +3092,8 @@ void VCS_SOLVE::vcs_dfe(const int stateCalc,
 
 void VCS_SOLVE::vcs_printSpeciesChemPot(const int stateCalc) const
 {
+    warn_deprecated("VCS_SOLVE::vcs_printSpeciesChemPot",
+                    "Unused. To be removed after Cantera 2.3.");
     double mfValue = 1.0;
     bool zeroedPhase = false;
 
@@ -3167,6 +3169,8 @@ void VCS_SOLVE::vcs_printSpeciesChemPot(const int stateCalc) const
 
 void VCS_SOLVE::prneav() const
 {
+    warn_deprecated("VCS_SOLVE::prneav",
+                    "Unused. To be removed after Cantera 2.3.");
     vector_fp eav(m_numElemConstraints, 0.0);
 
     for (size_t j = 0; j < m_numElemConstraints; ++j) {