Oh, I did use vinegar! I even let it sit for a while. I tried scrubbing with various methods for a good 3 hours yesterday, and these are the AFTER scrub pictures.

Also, I've already seen the grey tree frog care page. Thanks!

Are there any guides on exactly how to put in live plants, other than ones like the one I already bought that comes in a little plastic pot with some sort of gel in it?

Even before I knew philodendrons were ok to use, I was already rooting a cutting . . . . I just don't know how to implement it into the habitat.