Jpanhalt seems to know Eagle better than I. But there is another way you can do this, where you simply "break annotation." So this is only to be done if you want to panelize a Gerber, for instance. And this is what it sounds like you want to do.
Breaking annotation is as easy as closing the schematic window. A banner will appear in the PCB view window saying "ANNOTATION BROKEN!" Then you can copy and paste all you want. But you will no longer have a schematic linked to this board, and YOU CANNOT UNDO THIS AFAIK. (I'm surprised more people haven't done this accidentally at some point, and learned this the hard way). So make sure you save this to a new .brd file. If you need to make anything but minor tweaks in the future (or debug a problem with the board), you have to go back to the original .brd and do the work there, and copy and paste, again. Without a schematic, you can't do signal routing for instance. Or ERC check. Etc.