I personally think that doing a cleanse like Master-Cleanse may have some beneficial effect to the whole body so yes you will reap some benefit from the MC. Very clean living may eventually heal many things, but you can also target the liver and get very dramatic results if that happens to be an area that your body needs help on.
Another note: make sure you are doing some refeeding between cleanses in general. If you do too many back to back, your body will not be getting nutrition to rebuild itself. If your Master-Cleanse is short, I would think a liver cleanse may be okay after if you feel strong. It depends on your level of health and energy and how you eat before/after.
I like the standard Hulda ClarkLiver Flush (many details on different Liver-Flush methods on the Liver-Flush forum) - if you didn't have results, do it again! I've done a handful of Liver Flushes and I've had results. I read a lot about it and occasionally one doesn't seem to do much from what I read. I say try again then head on to the Liver-Flush Forum for more details. Good luck. :)