if it's only one or two male flowers on a predominently female plant go ahead and use the feminizer... but after a couple of years the ethelene in that would have degraded so it won't do much. Go ahead and buy dutchmaster reverse and penetrator and give it a good spray down, it couldn't hurt and it will preserve your current crop. If you want to spend less get sensa-spray but it can cause some wilting for a day or two. As for genetics, yeh don't make clones because you don't want these traits to be passed down.
Make sure to cut off those male flowers!