diff --git a/src/simsopt/mhd/spec.py b/src/simsopt/mhd/spec.py
index 05e304a52..ec7444417 100644
--- a/src/simsopt/mhd/spec.py
+++ b/src/simsopt/mhd/spec.py
@@ -141,6 +141,12 @@ def __init__(self,
                 filename = f"{filename}.sp"
             logger.info(f"Initializing a SPEC object from file: {filename}")
 
+        # If spec has run before, clear the f90wrap array caches.
+        # See https://github.com/hiddenSymmetries/simsopt/pull/431
+        # This addresses the issue https://github.com/hiddenSymmetries/simsopt/issues/357
+        if spec.allglobal._arrays:
+            self._clear_f90wrap_array_caches()
+
         if tolerance <= 0:
             raise ValueError(
                 'tolerance should be greater than zero'
@@ -716,6 +722,18 @@ def set_dofs(self, x):
             if p is not None:
                 p.phiedge = x[0]
 
+    def _clear_f90wrap_array_caches(self):
+        """
+        Clear the f90wrap array caches. This is necessary when a new file is
+        read after SPEC has run before.
+
+        See https://github.com/hiddenSymmetries/simsopt/pull/431
+
+        This function is for addressing the issue https://github.com/hiddenSymmetries/simsopt/issues/357
+        """
+        spec.allglobal._arrays = {}
+        spec.inputlist._arrays = {}   
+
     def init(self, filename: str):
         """
         Initialize SPEC fortran state from an input file.