Coding peeve

Am working on a new consulting gig, which is going pretty well. The code is a website, and like any large code base that has been modified by many people under time pressure over the years, it has its good and bad points. However, I keep seeing something that is a pet peeve: large chunks of code that are commented out, with no comment explaining why the code is commented out. I really do not think this adds anything. It also makes me wonder was something accidentally left commented out, or should the code have been deleted. There has been turnover in staff, and there is no one to ask. Have decided to delete most of it. Years ago, I worked with a tech writer who used to say "when in doubt, delete it out". That certainly applies here.