These collectibles are there for the full time. As I said I've watched them appear, but I can't touch them, can't pick them up. I've also noted that one cannot pick them up just before they are about to disappear, but these have been there for at least 10 seconds. Since this has only happened since I had several games running, I'm wondering whether or not it has to do with the other games--maybe it's on one of the other games, and just shows in the one I'm currently viewing. Just one of those weird things, but aggravating as anything when it's the one last item you're missing out of all the collectibles. :-(