diff --git a/pysatNASA/instruments/methods/general.py b/pysatNASA/instruments/methods/general.py
index 1bee292d..f51c42b8 100644
--- a/pysatNASA/instruments/methods/general.py
+++ b/pysatNASA/instruments/methods/general.py
@@ -68,6 +68,7 @@ def clean(self):
 
     for key in self.variables:
         # Check for symmetric dims
+        # Indicates transformation matrix, xarray cannot broadcast
         unique_dims = len(self[key].dims) == len(np.unique(self[key].dims))
         # Skip over the coordinates when cleaning
         if key not in coords and unique_dims: