Bottling with spin top growlers

I bought 2 1-gal growlers (full of beer) from Whole Foods a while ago, and I'm wondering if I can use them for bottling up some homebrew. They are twist tops though, so I don't know how long they will keep the carbonation. The beer that was in them was still carbonated a week later, despite having been opened several times, but should I be leery of using them, or just make sure I drink them rather quick?

I've done it and it worked well for me. Its not recommend because they can explode. If you do it, store them inside garbage bags. The one down side to them is that you have to decant the beer when you want to drink it. If you don't, you swirl up the yeast sediment from the bottom, by pouring one beer after another. Decanting 128oz of beer can be a pain in the ass...

I see, that could be a pain. I may give it a shot with my stout, maybe I'll bring that to Ohio for Xmas instead of a 6 pack.