I'm starting a octopus tank and i got some old rock from someone who used to have a fish only aquarium to use as base rock. The problem is that I'm pretty sure she used copper medicines in her aquarium. Does that mean the rock is pretty much unusable if I want a ceph in my aquarium? However its been on her back porch in buckets for the past five or six years and I've read that prolonged exposure to the elements can render the copper insoluble and/or leach it out. If not, is there any other way to "un-copper it"? If it's still water soluble, is there a way to expose the rock to enough water to leach out the bulk of what might be in there? Any advice would be greatly appreciated. Thanks.