Don't any of you remember the sitcom episode of the "Odd Couple" show, where Felix finds a dime in a payphone booth change slot, and dutifully reports it as income on his income tax return?
You guys, this whole "publication 535" stuff, and "keeping records of expenses verses income" stuff, is only for if you intend to declare it, TO BEGIN WITH! If you are not planning on declaring the income, then you don't need off-setting deductible expense records, as there is nothing declared anyhow.
And as I understand it, you DON'T have to declare it as income, unless you liquidated it (sold on ebay, cashed in your clad to spend, etc...) anyhow.
But I'll tell you all what, just as with Felix on the Odd-Couple, I agree that we should all be keeping the metal detecting "code of ethics", which has the clause "I will obey all laws". Therefore, in the interest of the furtherance of our great hobby, I will "take the fall" for everyone here. Simply send me all your finds in the mail (you pay postage), and I will absolve you of all guilt. I will handle any tax obligations, etc.... Consider this my self-sacrificing contribution to the benefit of all forum participants here. Yes yes I know, this is mighty kind of me, but it's the least I could do.