diff --git a/src/main/java/org/gcube/accounting/datamodel/BasicUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/BasicUsageRecord.java
index 3f50abe..f319bca 100644
--- a/src/main/java/org/gcube/accounting/datamodel/BasicUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/BasicUsageRecord.java
@@ -288,8 +288,8 @@ public abstract class BasicUsageRecord implements UsageRecord, Serializable {
 	 */
 	@Override
 	public void setResourceProperties(Map<String, Serializable> properties) throws InvalidValueException {
-		validateProperties(properties);
-		this.resourceProperties = new HashMap<String, Serializable>(properties);
+		Map<String, Serializable> validated = validateProperties(properties);
+		this.resourceProperties = new HashMap<String, Serializable>(validated);
 	}
 	
 	/**
@@ -400,11 +400,13 @@ public abstract class BasicUsageRecord implements UsageRecord, Serializable {
 		return checkedValue;
 	}
 	
-	protected void validateProperties(Map<String, Serializable> properties) throws InvalidValueException{
+	protected Map<String, Serializable> validateProperties(Map<String, Serializable> properties) throws InvalidValueException{
+		Map<String, Serializable> validated = new HashMap<String, Serializable>();
 		for(String key : properties.keySet()){
 			Serializable serializable = properties.get(key);
-			validateField(key, serializable);
+			validated.put(key, validateField(key, serializable));
 		}
+		return validated;
 	}
 	
 	/**
@@ -471,7 +473,6 @@ public abstract class BasicUsageRecord implements UsageRecord, Serializable {
 		}
 		return 1;
 	}
-
 	
 	@SuppressWarnings("unchecked")
 	protected static Class<? extends UsageRecord> getClass(String usageRecordName, boolean aggregated) throws ClassNotFoundException {