Identify the Top 3 searches having lots of alerts in the queue. Remove History from the Change Auditor client GUI console by doing a right click on the appropriate Search > Alert > Delete History
To identify top searches, run the following SQL query against Change Auditor live DB:
SELECT DISTINCT
Query.Information.QueryName,
dbo.AlertHistory.QueryID,
Count(dbo.AlertHistory.QueryID) AS Total
FROM dbo.AlertHistory with (NOLOCK)
JOIN Query.Information ON Query.Information.QueryID = dbo.AlertHistory.QueryID
GROUP BY Query.Information.QueryName, dbo.AlertHistory.QueryID
ORDER BY Total DESC;