diff --git a/archaius-core/src/main/java/com/netflix/config/ConcurrentCompositeConfiguration.java b/archaius-core/src/main/java/com/netflix/config/ConcurrentCompositeConfiguration.java
index bb97d2ac..a3e4402b 100644
--- a/archaius-core/src/main/java/com/netflix/config/ConcurrentCompositeConfiguration.java
+++ b/archaius-core/src/main/java/com/netflix/config/ConcurrentCompositeConfiguration.java
@@ -115,9 +115,16 @@ public class ConcurrentCompositeConfiguration extends ConcurrentMapConfiguration
     private final Set<String> usedProperties = ConcurrentHashMap.newKeySet();
 
     public Set<String> getUsedProperties() {
-        return usedProperties;
+        return Collections.unmodifiableSet(new HashSet<>(usedProperties));
     }
 
+    public Set<String> getAndClearUsedProperties() {
+        synchronized (usedProperties) {
+            Set<String> ret = getUsedProperties();
+            usedProperties.clear();
+            return ret;
+        }
+    }
 
     private List<AbstractConfiguration> configList = new CopyOnWriteArrayList<AbstractConfiguration>();
     
diff --git a/archaius-core/src/test/java/com/netflix/config/ConcurrentCompositeConfigurationTest.java b/archaius-core/src/test/java/com/netflix/config/ConcurrentCompositeConfigurationTest.java
index 73416fe7..493d09c5 100644
--- a/archaius-core/src/test/java/com/netflix/config/ConcurrentCompositeConfigurationTest.java
+++ b/archaius-core/src/test/java/com/netflix/config/ConcurrentCompositeConfigurationTest.java
@@ -18,6 +18,7 @@
 import static org.junit.Assert.*;
 
 import java.util.List;
+import java.util.Set;
 
 import org.apache.commons.configuration.AbstractConfiguration;
 import org.apache.commons.configuration.BaseConfiguration;
@@ -80,11 +81,24 @@ public void testInstrumentation() {
         config.addProperty("prop1", "val1");
         config.addProperty("prop2", "val2");
         assertEquals(config.getProperty("prop1"), "val1");
-        assertEquals(config.getUsedProperties().size(), 1);
-        assertEquals(config.getUsedProperties().iterator().next(), "prop1");
+
+        // Confirm that the usage is captured
+        Set<String> usedProperties = config.getUsedProperties();
+        assertEquals(usedProperties.size(), 1);
+        assertEquals(usedProperties.iterator().next(), "prop1");
+
+        // Confirm that an uninstrumented call is ignored
         assertEquals(config.getPropertyUninstrumented("prop2"), "val2");
-        assertEquals(config.getUsedProperties().size(), 1);
-        assertEquals(config.getUsedProperties().iterator().next(), "prop1");
+        usedProperties = config.getAndClearUsedProperties();
+        assertEquals(usedProperties.size(), 1);
+        assertEquals(usedProperties.iterator().next(), "prop1");
+
+        // Confirm that both usedProperties endpoints respect when the properties have been cleared
+        usedProperties = config.getUsedProperties();
+        assertTrue(usedProperties.isEmpty());
+
+        usedProperties = config.getAndClearUsedProperties();
+        assertTrue(usedProperties.isEmpty());
 
         System.clearProperty(ConcurrentCompositeConfiguration.ENABLE_INSTRUMENTATION);
     }