So it sounds like a schedule C along with a COGS equal to what I paid would be the best route?
It's not a business. You're selling items you held for personal use and you should rightfully get capital gains treatment. If you can't show what you paid for the items then it's not a good idea to report a COGS number equal to what you paid because you obviously can't prove what you paid. You'd be better off listing these items as capital assets....which is what they are....and reporting a zero basis provided you can show that you've held them for longer than a year.
The case with the IRS agent discussed in another message is very different than yours. That agent sold thousands and thousands of items of clothing over several years which were advertised as new and were many different sizes.
