What are you using to mark volumes?

I'd prefer an indentation, but as thin as some of these pots have become I'm concerned I'll do damage. What kind of tool do you use?

If you use a permanent marker with non-toxic ink, what marker are you using?

I have guessed at volumes since I replaced my measuring cup/drinking cup.

post on this topic:

http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/14190/index.html?skip_to_post=105539#105539

Tim, without the benefit of reading the above link, I thought I'd just plow ahead and share what I did. First, I used separate measuring cups for each respective gradient (1/4C, 1/3C, etc). That way the measure would be more accurate. Then, using a glass cutting wheel, I scribed a 1/2 inch line at the meniscus as I poured in each successive amount of water. It turned out to be pretty accurate, or as accurate as I need it to be out in the boonies. Happy trails!

yeah i just scratched a line at 2 cups. you can eyeball 1 cup and 3 cups easily