System.Diagnostics.EventLog Safe Clearing of the logs

Can anyone give me a couple pointers on safely clearing the logs? We have an
extremely active environment and I am worried that even after I dump all the
entries a dozen or so new ones will be created before I can call the Clear
method. If this happens I am guessing that I will throw away any entries
that get created between the time my dump process finishes and the time I
call Clear. How can I safely clear only those entries that I know I have
processed? I was hoping I could clear only up to a praticular index rather
than clearing the entire thing.

Thanks!