The short answer is no. Don't use that tank.
The longer answer is maybe. There are a number of media out there that claim to remove copper traces. If you really want to try it, give those things a good run, well beyond when you test 0 for copper, then wait a while, then use those again for a while. Keep up water changes during this process. The worry is that your tank/rock/substrate may have absorbed some copper than will leach back into the water, so keep chaning water and using some media to absorb any copper.
After a month or two of that routine, assuming you test for 0 copper for some time, I don't think you could be blamed for adding a single hardy coral to see what happens.
There are no guarantees here, but hopefully someone with specific experience can provide more info.
Tim