Appreciate the positive contribution and suggestion. None of the stuff I wanted to unload has any piece of paper associated with it. I was negotiating with my wife about this. She has tons of pricey purse she collected over the years(decades) and I have numerous audio equipment over the decades also worth a bit. We're both near retirement and need to downsize and each want to get rid of the other's stuff. We toyed around with maybe unloading on ebay as vintage purse holds their value really well. Pretty much any single piece of item we sale will probably go past that $600 limit and at this point that's enough reason for neither of us to sale anything. Maybe some of her more recent purchase within the previous 5 years she might be able to call CS and get a receipt...just not worth the effort at this point. If the burden of proof is on the IRS auditors....maybe. We'll wait a few more years and see how the IRS goes after people before selling.
Again, the tax is ONLY on the profits. If you sold those for over $600 did you actually have profits? If not, then you owe $0 in taxes. Very few people have paper receipts from years ago. Even if you did, the ink may have faded beyond recognition. That is why the IRS doesn't require receipts. The IRS requires fair market value estimations.
Suppose your wife bought a pricey purse years ago for somewhere around $100 but can't actually remember and has no receipt. Suppose she sells it on Ebay for $800 and got a 1099. You would profit roughly $700 on that sale. It is a long term capital gain with a tax rate of 0% if you as a couple make less than $94,050. Your tax is 0% * $700 = $0.
Or lets suppose your income is above that $94,050 limit, but below $583,750, then your long term capital gains tax rate is 15%. So you owe 15% * $700 = $105 in long term capital gains taxes.
Point 1) You would give up $700 in profit to avoid $105 in tax? Seems counterintuitive to do so.
Point 2) Suppose that purse was actually $80 when she bought it and not $100. You don't have the receipt, so you can't prove it's actual cost. Now the long term capital gain is $720 and the tax is 15% * $720 = $108. The difference is a grand total of $3 from what was estimated of $105. The tax tables themselves go up in intervals of ~$11, see the image below of the 2023 tax table. The IRS doesn't care about differences that small, below accuracies of what even the tax table requires. Thus, slight differences in estimates of the value of the purse is totally meaningless. All you have to do is make a reasonable attempt to be accurate. Or in the very worst case scenario extreme, if the IRS thinks she magically got these pricey collectable purses for free, the whole tax due is $120 and you'd owe $15 more. How many hundreds / thousands of dollars would the IRS spend hunting you down for that $15? Hint, they don't.
Point 3) If you do multiple sales, you probably underestimate some and overestimate some fair market values. Thus, your small inaccuracies are a wash. That is, unless you are purposely estimating incorrectly.
Point 4) You owe that tax on a sale whether or not you got the 1099. The 1099 just helps the IRS flag there is a potential for profit on pricey items.