Most of what the renovator does is remove dirt, it is a very mild cutting compound and if the frame doesn't have clear coat then it will take off a little paint together with the dirt. If the frame has a clear coat then it is going to scrape off dirt. I find it is the dirt that dulls the appearance of the paint more than anything. Just be careful with the renovator on loose, flaky transfers, I normally wipe up to and around them if they aren't stable enough. All I avoided on this frame was the Reynolds 753 frame transfer, everything else was ok to wipe over.
This was SB5084 before cleaning...
and after some rust treatment and cleaning...
and this is before and after on SB1861...
This is the polishing cloth I use...
I would recommend cleaning a less obvious place such as under the chainstays and BB first as a test to see how you go before attacking something more prominent.