Over the years I've read (often here at Mudcat) about the solid quality of some of the older receivers compared to what is produced today. And in general, they go for a nice price on eBay if they work or if you sell them "for parts or repair." Finding them is the trick, and getting them into the hands of those who do the repairs means some profit for me and probably a lot more profit for them (after they add the value of the repair). I find (online) and include the owners manual and usually find the remote control, if there was one (they're all sold on eBay).

There are other smaller things also. You have to stick with what you know there is a market for. The beauty of smart phones is that while in a thrift store or at an estate sale you can look up and item and find if there is a reasonable market for it.

I was watching one of those cable house remodeling programs this weekend and cringed when they took a nice antique brass chandelier and painted it chartreuse. Yuck. But someone probably sold it to them and made some money doing it.