Short answer: You can't.

Long answer: You can, but you have to stop using it first. That doesn't mean just the data in `/etc`, it means in file ownership throughout all your filesystems. If it is used in `/dev`, things may get hairy. It may also mean in possible future installs, depending on your distribution. (And some distributions may restore things they stock install as you upgrade.)

As for comments: I wouldn't count on a comment syntax. (Version 7 documents no comment syntax.) You might just be changing the name. (Though I will admit, "#" comments do seem to work for me, even with busybox!)