Kinda. You can't do a regular double spend, where you spend the same currency twice (And thus get twice the value out of it, kinda). You could spend the coins i

Kinda. You can't do a regular double spend, where you spend the same currency twice (And thus get twice the value out of it, kinda). You could spend the coins in ETH, and then spend the coins in ETC, two different currencies worth different amounts. The catch is that there is no guarantee you come out ahead, like there would normally be with a double spend. The fork resulted in a price drop (That has now somewhat recovered), and ETC is not worth nearly as much as ETH (About a 10:1 ratio). So ETC+ETH is really not worth much more then ETH was originally before the fork, if it is at all - even if you spend both, you probably didn't make any money on the fork itself.