Where are sales like this posted?
Call any of the local auction houses around you.
They get paid a percentage of the returns, so they are incetivized to attract as many bidders as possible. They want you there.
Many have email list you can get on.
Be prepared though for the opportunity. You need a place to store it. Often you need to take it right then and there. So see if you can find a box truck. A lot of the ones we go to are industrial type auctions, we want the small stuff, which scrap and industrial guys do not. They are often mixed in, on purpose, the junk with the good, just to get rid of it. So team up with someone, like my friend did( I wish he kept the generators, but he doesn’t know squat about them )
Have money, a truck, place to store, be flexible, have a drive, get lunch, and in this case see the busting out of, sell out, of a once great nations artifacts.