diff --git a/CHANGELOG.md b/CHANGELOG.md
index 074e591272..9f9cba998a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Fix `Money::Currency.reset!` keeping the cached key set, so a currency registered before the reset was still accepted by `Money::Currency.new` and raised `NoMethodError` instead of `UnknownCurrency`
 - Fix `Money::Bank::VariableExchange#import_rates` parsing `:json` with `JSON.load`, which instantiates any class named by a `json_class` key; it now uses `JSON.parse`
 
 ## 7.1.1
diff --git a/lib/money/currency.rb b/lib/money/currency.rb
index 1b630fe37a..d4e96be88e 100644
--- a/lib/money/currency.rb
+++ b/lib/money/currency.rb
@@ -217,6 +217,7 @@ def each(&)
       def reset!
         @@instances = {}
         @table = Loader.load_currencies
+        @stringified_keys = nil
         clear_iso_numeric_cache
       end
 
diff --git a/spec/money/currency_spec.rb b/spec/money/currency_spec.rb
index 6252fc2b91..1b809d7f22 100644
--- a/spec/money/currency_spec.rb
+++ b/spec/money/currency_spec.rb
@@ -533,5 +533,16 @@ def to_s
       described_class.reset!
       expect(described_class.find(:cad).decimal_mark).not_to eq modified_mark
     end
+
+    it "drops a registered currency it no longer holds" do
+      described_class.register(iso_code: "ZZZ", subunit_to_unit: 100, priority: 1)
+      described_class.new("ZZZ")
+
+      described_class.reset!
+
+      expect(described_class.find(:zzz)).to be_nil
+      expect { described_class.new("ZZZ") }
+        .to raise_error(described_class::UnknownCurrency)
+    end
   end
 end