From a link at www.copper.org : Paper in American Society for Microbiology from 2018 : Rapid inactivation of human coronavirus occurs on brass and copper nick

From a link at www.copper.org : Paper in American Society for Microbiology from 2018 : Rapid inactivation of human coronavirus occurs on brass and copper nickel surfaces at room temperature (21°C).Brasses containing at least 70% copper were very effective at inactivating HuCoV-229E (Fig. 2A), and the rate of inactivation was directly proportional to the percentage of copper. Approximately 103 PFU in a simulated wet-droplet contamination (20 µl per cm2) was inactivated in less than 60 min. Analysis of the early contact time points revealed a lag in inactivation of approximately 10 min followed by very rapid loss of infectivity (Fig. 2B). As observed previously for norovirus, zinc demonstrated a slight antiviral effect compared to that seen with stainless steel (neither metal contains copper). As I said, looks like can do better than 4 hours, copper is the key metal for the action. There is much more, I had thought anyone who was interested could find it all for themselves, but apparently not. Further info is available by searching "copper coronavirus inactivation". Like this from the ICU Management and Practice Bulletin, origin Southhampton Unisversity : During simulated fingertip contamination, the research team observed that the corona virus was inactivated within a few minutes of being exposed to copper or copper alloys (collectively termed "antimicrobial copper"). There is more, but a picture emerges, and it might be useful.