Normal - it's thought to be an attractant for ants, which in turn harvest the sap for food and protect the plant from invaders.

Thanks for the response, cactusmcharris. That's really interesting! I don't really want ants on my porch and I already kinda have a problem with them. Can I rinse it off? Or do you think this small of an amount won't create a problem?

That symbiosis is for in-habitat plants - I don't think you'll need to wash it off.

Okay, thanks for sharing your knowledge. :)

Thanks for sharing this piece of information! I was extremely puzzled with my ferrocactus this past weekend when I saw this clear-ish liquid, and when I tried to remove it with a q-tip it's actually STICKY!

Good to know it's a natural reaction on the plant's part.