diff --git a/src/fr/devinsy/sikevadb/SQLSikevaDB.java b/src/fr/devinsy/sikevadb/SQLSikevaDB.java
index 29fe99c..f61e883 100644
--- a/src/fr/devinsy/sikevadb/SQLSikevaDB.java
+++ b/src/fr/devinsy/sikevadb/SQLSikevaDB.java
@@ -186,6 +186,7 @@ public class SQLSikevaDB implements SikevaDB {
 	 */
 	@Override
 	public void clearArchive(final Date beforeDate) throws SQLException {
+		//
 		if (beforeDate == null) {
 			throw new NullPointerException("beforeDate is null.");
 		} else {
@@ -197,9 +198,9 @@ public class SQLSikevaDB implements SikevaDB {
 				//
 				connection = getConnection();
 				connection.setAutoCommit(true);
-				statement = connection.prepareStatement("DELETE FROM elements WHERE ARCHIVE_DATE<?");
+				statement = connection.prepareStatement("DELETE FROM elements WHERE ARCHIVE_DATE IS NOT NULL AND TO_SECONDS(ARCHIVE_DATE)<?");
 
-				statement.setTimestamp(1, dateToTimestamp(beforeDate));
+				statement.setLong(1, beforeDate.getTime() / 1000);
 
 				statement.executeUpdate();
 
@@ -214,6 +215,10 @@ public class SQLSikevaDB implements SikevaDB {
 	 */
 	@Override
 	public void clearArchive(final int maxDays) throws SQLException {
+		//
+		logger.debug("maxDays={}", maxDays);
+
+		//
 		if (maxDays < 0) {
 			throw new IndexOutOfBoundsException("maxDays is negative.");
 		} else {