diff --git a/app/controllers/spree/admin/payment_methods_controller.rb b/app/controllers/spree/admin/payment_methods_controller.rb
index 077cddbca8..6398f02f65 100644
--- a/app/controllers/spree/admin/payment_methods_controller.rb
+++ b/app/controllers/spree/admin/payment_methods_controller.rb
@@ -197,10 +197,16 @@ module Spree
 
       def clear_preference_cache
         @payment_method.calculator.preferences.each_key do |key|
-          Rails.cache.delete(@payment_method.calculator.preference_cache_key(key))
+          delete_from_cache @payment_method.calculator.preference_cache_key(key)
         end
       end
 
+      def delete_from_cache(cache_key)
+        return unless cache_key.class.in? [String, Integer, Float, Symbol]
+
+        Rails.cache.delete(cache_key)
+      end
+
       def add_type_to_calculator_attributes(hash)
         hash["calculator_attributes"]["type"] = hash["calculator_type"]
       end