Unless we have a big bull run, most 400 series and 500 series AMD will be idle, sold or trashed. Right now its not worth mining anything else. My cards have been ruining for almost 3 years and i plan on them being worthless, when if ever eth goes POS.
Consider yourself one of the lucky ones then because the RX 470/570 were pretty cheap cards to begin with and you got great hash and great power consumption. So if you were mining in Late 2017...Early 2018 you probably ROI it multiple times.
The people that got it rough are the ones who got in the game in Q2 2018 and ended up paying an inflated price of $1000 for a 1080Ti GTX. Sure its Nvidia gamers love it but there is no way they could ROI on that GPU even if they sold it second hand.
Most likely if the fans are still good, just sell it in pairs and some gamer will buy them and Crossfire them. As long as the price is right they should sell. Most of the computers parts will sell except maybe the mining frames and risers which will definately be useless.